"Do you remember his phone number? I don't suspect so."

Options

A. don't think
B. don't thing
C. may think
D. No Improvement

Answer

A

Explanation

(1) don.t think so (Idiom): used for saying very strongly that you do not agree to something, or that something is not possible
suspect (Verb.) : to be suspicious about something, not to trust something
Here, don.t think is the right usage.