Which of the mathematical signs should be interchanged in the below equation to make it mathematically correct?
$$14 + 63 \div 7 - 21 \times 35 = 140$$

A

$$+$$ and $$-$$

B

$$+$$ and $$\times$$

C

$$-$$ and $$\times$$

D

$$\div$$ and $$\times$$