Correct Answer: Enthusiastic

Solution : The correct choice is the second option.

The word keen has a few potential synonyms, but the most appropriate one among the options provided would be enthusiastic.

The meanings of other words are as follows:

• Happy refers to a feeling of pleasure, contentment, or a general state of being content or joyful.
• Wild means untamed, unrestrained, or uncontrolled.
• Enthusiastic: This is the most appropriate synonym for keen among the options provided. Enthusiastic means showing intense and eager enjoyment, interest, or approval for something.
• Imitate means to copy or mimic something.

Therefore, among the given options, enthusiastic is the most appropriate synonym for keen, as it conveys a similar sense of eagerness, interest, and intensity towards something.