Explanation:

Here’s the thing—let’s break down each option, plain and simple:

- Option 1: let herself go

This is the right choice. “Let herself go” means to stop caring about one’s appearance or self-care, which fits perfectly in this sentence after mentioning her divorce.

- Option 2: let herself gone

Not correct. The phrase doesn’t make sense in English; the grammar’s off.

- Option 3: let her go in

This isn’t used in this context. “Let her go in” would mean allowing someone to enter a place—not relevant here.

- Option 4: let herself going

Also incorrect, doesn’t fit grammatically and has no recognized meaning.

So, your answer is spot on.