Correct option is B
Given equation,
840 ÷ 38 − 7 + 10 × 12 = 462
As per the question interchange 12 and 38, × and –
840 ÷ 12 × 7 + 10 - 38 = 462
70 × 7 + 10 - 38 = 462
490 + 10 - 38 = 462
500 - 38 = 462
462 = 462
Therefore, the correct answer is (b).