Answering your phone is an example of
a.
providing feedback
b.
choosing a sound to focus on
c.
making an effort to attend
d.
making an effort to remember

b.

choosing a sound to focus on

Explanation:

Remembering, attending, or providing a feedback are not represented by the action of answering a phone. There's no direct connection between those 3 and the action itself, but you can consider that by answering a phone, you're choosing to focus on something.

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