Which verb agrees with the subject of the sentence?
The weather forecast of violent
thunderstorms what changed our
plans to go boating.
A. are
B. is
C. were

the answer is B

Explanation:

Definitely, the the only right answer from the scale represented above is the first option: a. accepting more uncertainty than usual. The rest of options do not refer to the definition of tolerating ambiguity so  I am pretty sure that the first one is correct.

To conclude: the full definition should look this way :

Tolerating ambiguity means accepting more uncertainty than usual.