Your guess is as good as mine

Do you know the English phrase “Your guess is as good as mine“? Look at the conversation below. Can you guess the meaning?

Janet: Why did Paul leave the party early last night?

Freddie: Your guess is as good as mine. I thought he was having a good time.

Janet: Maybe he wasn’t feeling well…

Does it mean 

a) please guess

b) I don’t know/I have no idea

c) I guessed but I was wrong

d) you know more than me

The answer is below! ↓

 

Answer: b) I don’t know/I have no idea