Those who get a thrill out of being "right" may be disappointed by the rollout, which says that the two plays are TCTC
I get a thrill out of knowing and prefer being correct. I won't settle for a better answer when it's so easy to get and at my fingers so below are a couple of rollouts of the 31. Thanks to my hard work we can see when comparing to your rollouts that I completely wasted my time.
*Note the second roll out is the 31 same position/same seed rolled out 5ply/4ply. This only took 21 minutes to get 1296 trials and I recommend we do this when possible for positions near the end of the game like this one.
Given with the 31 that play A wins basically 3% more games than play B and play A loses only 4% more gammons (exactly twice as many as play B) you'd think play A would be ahead by more wouldn't you? It may just be too early in the day for me to think about this...
Note also that, if you believe the absolute equity numbers, GNU considers 3-1 to be the worst roll of the lot.
Agree of the bunch 31 is clearly the worst.

              
                   
 | is Player 2
score: 0 pip: 21 | Money session Jacoby Beaver | pip: 66 score: 0
is Player 1 | |
XGID=-CBCBCA-------------aAbdb-:1:1:1:31:0:0:3:0:10 |
to play 31 |
1. | Rollout1 | 21/20* 20/17 | eq: -0.284 |
| Player: Opponent: | 33.29% (G:0.00% B:0.00%) 66.71% (G:8.06% B:0.14%) | Conf: ± 0.001 (-0.285...-0.283) Duration: 2 minutes 35 seconds |
|
2. | Rollout1 | 21/20* 6/3 | eq: -0.287 (-0.003) |
| Player: Opponent: | 30.25% (G:0.00% B:0.00%) 69.75% (G:0.40% B:0.01%) | Conf: ± 0.001 (-0.288...-0.286) Duration: 57.7 seconds |
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1 46656 Games rolled with Variance Reduction. Dice Seed: 1296 Moves and cube decisions: 3 ply
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 | is Player 2
score: 0 pip: 21 | Money session Jacoby Beaver | pip: 66 score: 0
is Player 1 | |
XGID=-CBCBCA-------------aAbdb-:1:1:1:13:0:0:3:0:10 |
to play 13 |
1. | Rollout1 | 21/20* 20/17 | eq: -0.282 |
| Player: Opponent: | 33.31% (G:0.00% B:0.00%) 66.69% (G:8.26% B:0.13%) | Conf: ± 0.004 (-0.286...-0.278) Duration: 14 minutes 23 seconds |
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2. | Rollout1 | 21/20* 6/3 | eq: -0.283 (-0.001) |
| Player: Opponent: | 30.29% (G:0.00% B:0.00%) 69.71% (G:0.39% B:0.01%) | Conf: ± 0.004 (-0.287...-0.279) Duration: 6 minutes 49 seconds |
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1 1296 Games rolled with Variance Reduction. Dice Seed: 1296 Moves: 5 ply, cube decisions: 4 ply
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 | is Player 2
score: 0 pip: 21 | Money session Jacoby Beaver | pip: 66 score: 0
is Player 1 | |
XGID=-CBCBCA-------------aAbdb-:1:1:1:41:0:0:3:0:10 |
to play 41 |
1. | Rollout1 | 21/20* 6/2 | eq: -0.263 |
| Player: Opponent: | 31.25% (G:0.00% B:0.00%) 68.75% (G:0.42% B:0.01%) | Conf: ± 0.001 (-0.264...-0.262) Duration: 53.9 seconds |
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2. | Rollout1 | 21/20* 20/16 | eq: -0.263 (-0.001) |
| Player: Opponent: | 33.92% (G:0.00% B:0.00%) 66.08% (G:7.52% B:0.14%) | Conf: ± 0.001 (-0.264...-0.262) Duration: 2 minutes 13 seconds |
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1 46656 Games rolled with Variance Reduction. Dice Seed: 1296 Moves and cube decisions: 3 ply
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