✔ Correct Answer: A. The pen wasn't writing, it must have run out of ink.

The correct answer to the question “Choose the sentence which is grammatically correct: The pen wasn't write, it must run out of ink.” is The pen wasn't writing, it must have run out of ink.. This question belongs to Grammar Concepts & Terms in English. Practice the related questions below to master this topic for your FPSC, PPSC and NTS tests.