The LCM of 84 , 105 and 140 is :

Correct option is D

Given:

Numbers  84 , 105 and 140

Solution: 

$$84 = 2\times 2 \times 3 \times 7 \\\ \\105 = 3\times5\times 7 \\\ \\140 = 2\times 2 \times 5 \times 7$$   

LCM = $$2\times 2 \times 3 \times 5 \times 7$$​

         = 420