Clam up

Do you know the English expression “clam up“? Read the conversation below. Can you guess the meaning?

Tanya: How was your job interview?

Rita: Oh it was terrible. When they asked me why I wanted to work there, I clammed up. I couldn’t think of anything to say!

Does it mean:

a) become tense

b) become forgetful

c) become silent

d) become amused

The answer is below! ↓

 

 

Answer: c) become silent