Which two signs should be interchanged to make the given equation correct?

$$(72 \div 18) + 30 \times 8 - 4 = 20$$

By Trial and Error method,

Option A

$$(72\div18)-30\times8+4=20$$

$$4-30\times8+4=20$$

$$4-240+4=20$$

$$-232=20$$

Hence Option A is incorrect

Option B

$$(72\div18)\times30+8-4=20$$

$$4\times30+8-4=20$$

$$120+8-4=20$$

$$124=20$$

Hence Option B is incorrect

Option C

$$(72\times18)+30\div8-4=20$$

$$1296+30\div8-4=20$$

$$1296+3.75-4=20$$

After solving the  value will be decimal which is not possible

Option D

$$(72+18)\div30\times8-4=20$$

$$90\div30\times8-4=20$$

$$3\times8-4=20$$

$$24-4=20$$

$$20=20$$

Hence, the correct answer is Option D