It’s not raining so we . . . . . not . . . . . an umbrella.

A. were , using

B. are , using

C. are , not using

D. will be , use

Answer: Option B

Solution(By Examveda Team)

Sentence is in present continuous tense.
Rule :
Subject + is/am/are + V-ing + other agents.
It’s not raining so we are not using an umbrella.