Correct option is A
The correct passive voice of the given sentence is (a).
Rules for converting active to passive voice:
1.
Active Voice Structure:
·
Subject + is/am/are + verb-ing + object
· "Suma is making tea."
2.
Passive Voice Structure:
·
Object + is/am/are + being + past participle + by subject
· "Tea is being made by Suma."
Example:
·
Active: She is painting a picture.
·
Passive: A picture is being painted by her.