han roshi sailor sakura azure fang in full healing mode should work, but maybe not at 50k power.

You could try iruka, normal naruto, gaara too with crimson fist full shielding mode.

beware that you absolutely need iruka to beat exam 140.

Or you go iruka, kurenai, lee eight inner gates, crimson fist lineup or come back at 75k+ power because is the only lineup that beat it under that power.

So get iruka if you don't own him or after you beat 137 you'll be struck for a long time at 140 without him.

Anyways, since you don't own many of the key ninjas, you are in an objective bad situation.

Your only option is to fully bet on luck, also know as: multiple shark bomb critical hits + poison delivered

Tell us what are your current ninjas and we can help you.

EDIT: you could try ao, yagura, utakata/snake cloak kabuto with azure fang. Should work with enough luck if you run 23322 talents and you use ao as 1st prompt move mystery on ay 4th and you copy darui with yagura as soon as you get the 40 chakra to do it. In round 2 you need to target cee with shark bomb (2nd prompt move) and to hope to target and chaos as a collateral target Sasuke Susano'o to prevent his mystery landing. Remember you are betting on luck, so could be you need 30-40-50 tries to win.

A lineup distribution could be:

Utakata/Kabuto SC Ao x

Yagura Azure Fang x

x x x