Question

which sentence uses this meaning of expression?
expression noun a way of saying something
as an expression of gratitude for helping her move, katie baked us a pie.
katies expression showed that she was delighted about rebeccas surprise visit.

Explanation:

We need to find the sentence where "expression" means "a way of saying something". In the first sentence, "expression of gratitude" uses "expression" to mean a way of showing (saying) gratitude. The second sentence uses "expression" to mean a facial expression. So the first sentence fits the given meaning.

Answer:

As an expression of gratitude for helping her move, Katie baked us a pie.