Which two signs should be interchanged to make the given equation correct?
156 ÷ 12 − 4 × 65 + 87 = 74

Logic: interchange mathematical operators and solve as per BODMAS rule.

​$$\begin{array}{|c|c|} \hline \textbf{Operation preference wise} & \textbf{Symbol} \\\hline Brackets &[],{}, () \\ \hline Orders, of & (power), √ (root) , of \\ \hline Division& ÷ \\ \hline Multiplication & × \\ \hline Addition & + \\ \hline Subtraction & - \\\hline \end{array}$$​​

156 ÷ 12 − 4 × 65 + 87 = 74

After interchanging,

156 ÷ 12 + 4 × 65 - 87 = 74

13 + 260 - 87 = 74

186≠74

So, its not correct option.

156 ÷ 12 − 4 × 65 + 87 = 74

After interchanging,

156 ÷ 12 − 4 = 65 + 87 × 74

13 − 4 = 65 + 6438

9≠6503

So, its not correct option.

156 ÷ 12 − 4 × 65 + 87 = 74

After interchanging,

156 ÷ 12 × 4 - 65 + 87 = 74

13 × 4 - 65 + 87 = 74

52 - 65 + 87 = 74

So, its correct option.

156 ÷ 12 − 4 × 65 + 87 = 74

After interchanging,

156 ÷ 12 − 4 × 65 = 87 + 74

13 − 260 = 87 + 74

-247≠161

So, its not correct option.

Thus, option C is correct.