Which two numbers (not digits) and which two signs should be interchanged to yield the value ‘zero’ for the following expression?

13 + 65 ÷ 2 × 8 – 21​​

Given: 13 + 65 ÷ 2 × 8 – 21​​

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

A) + and ÷; 13 and 21

= 21 ÷ 65 + 2 × 8 – 13

B) + and ÷; 13 and 65

= 65 ÷ 13 + 2 × 8 – 21

= 5 + 2 × 8 – 21

= 5 + 16 – 21

= 21 – 21

Thus, correct option is (b).

​