The weakness could ........................ if you tried hard to improve your standards.

A: This is a verb in the present tense, but in this sentence, we need the verb form that indicates the possibility of overcoming the weakness in the future, not a general statement about the present.

B: This is the past tense form of the verb "overcome." However, it doesn't fit the context because the sentence is discussing a possibility in the future, not something that already happened in the past.

C: This is the correct choice. It is the passive voice construction indicating that the weakness has the potential to be overcome in the future. The phrase "be overcome" suggests the action of overcoming taking place.

D: This is in the present perfect tense, indicating that the action of overcoming has already happened. However, the sentence is discussing the possibility of overcoming the weakness in the future, not stating that it has already been overcome.

Therefore, Option C is the correct answer.