A. The ‘Gitanjali’ was written by Rabindranath Tagore.
B. The ‘Gitanjali’ is written by Rabindranath Tagore.
C. The ‘Gitanjali’ is being written by Rabindranath Tagore.
D. The ‘Gitanjali’ has been written by Rabindranath Tagore.
Given sentence is in simple past tense and it is in active voice, we need to change it into passive voice.
Rule :
Subject + (was / were) + V3 + Optional Agents.