In order to solve such problems in the examination, the option-based approach is the best. Even if you can find out the required expression mathematically, it is advisable to solve through the options as this will end up saving a lot of time for you. Use the options as follows:

If we put n = 1, we should get the sum as 1.2.4 = 8. By substituting n = 1 in each of the four options we will get the following values for the sum to 1 term:

Option (a) gives a value of: 6 Option 

(b) gives a value of: 8 Option 

(c) gives a value of: 6 Option 

(d) gives a value of: 8 

From this check we can reject the options (a) and (c). 

Now put n = 2. You can see that up to 2 terms, the expression is 1.2.4 + 2.3.5 = 38.

The correct option should also give 38 if we put n = 2 in the expression. Since, (a) and (c) have already been rejected, we only need to check for options (b) and (d). 

Option (b) gives a value of 38. 

Option (d) gives a value of 80. 

Hence, we can reject option (d) and get (b) as the answer