Identify whether the bolded section of this sentence is a clause or a phrase.

The little turtle had a big smile on its face WHILE IT ATE THE STRAWBERRY.

Choose 1

(Choice A)
A
phrase

(Choice B)
B
clause

it's a clause

Explanation:

while is a joining word like but or because

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.