Which of the mathematical signs should be interchanged in the below equation to make it mathematically correct?
$$135 \div 15 \times 54 + 6 - 18 = 252$$

A

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

B

$$+$$ and $$-$$

C

$$\div$$ and $$+$$

D

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