Correct Answer: Believable

Solution : The correct choice is the fourth option .

The adjective "incredible" means something unbelievable, extraordinary, or difficult to believe due to being extraordinary or improbable.

Its antonym is the adjective "believable". It refers to something believable, which means it can be accepted as true or credible.

The meanings of the other options are as follows:

The adjective s trained describes something that is stretched or forced, often indicating difficulty or tension.

The adjective far-fetched describes something unlikely and often requires a creative leap of the mind.

The adjective implausible describes something that is not likely to happen or be true; it doesn't seem reasonable or probable.

Therefore, the correct antonym is believable.