All students who attempted a multiple choice question with wrong answer options in the history paper will be given one mark each, the Higher Secondary council said on Monday.

The one-mark question asked in which year the Nanking Treaty was signed. The four options were 1841, 1843, 1844 and 1845. None is correct as the treaty was signed in 1842.

When students pointed out the error after taking the history test on February 22, several teachers lodged a complaint with the West Bengal Council of Higher Secondary Education.

Council president Mahua Das said the decision to award the full mark to everyone who attempted the question was taken after speaking to history experts.

Das said the treaty became effective in 1843. The person who set the paper cited this as the reason for not providing 1842 as an option, she said. "But this explanation cannot be accepted as students had specifically been asked in which year was the treaty signed. The mistake should not have occurred and it should have been rectified during the final scrutiny of the question paper."

She said the council was looking into another complaint that students had to answer wrong sets of question papers. Students will be compensated if the complaint is found to be true, she said.