Correct Answer: Strong

Solution : The correct answer is the first option.

Explanation: In the context of antonyms, feeble is opposite in meaning to strong. 
Feeble is an adjective indicating a lack of strength or weakness, while strong is its direct opposite, denoting a high degree of power or vigour. When choosing antonyms, it's essential to consider the relationship between the words and how they relate to each other in terms of meaning.

The meanings of the other options are as follows:

• Frail: This term means weakness or delicate health.
• Weak: This refers to a lack of strength or vigour.
• Soft: This term implies a lack of hardness.

Therefore, the correct antonym is strong.