~たらよい (should, advice)

She advised me on which one to buy.

She was at a loss as to which road to take.

She was at a complete loss for what to do.

Could you tell me how to get to the baseball stadium?

The question is what I should do next.

If he happens to come, what should I say?

She didn't know what to say to him.

She told me which clothes I should wear.

She asked me where she should go.

The question is which one to choose.