Correct option is D
Given equation,
(31 × 3) - (27 × 4) + (81 ÷ 9) = 126
As per question after changing 27 and 9, + and – , apply the BODMAS rule-
(31 × 3) + (9 × 4) - (81 ÷ 27) = 126
93 + 36 – 3 = 126
129 – 3 = 126
126 = 126
Thus, the correct answer is (d).