Which of these could be the total cost of the pens?

The answer is Rs 173. It is a simple question. If we have to find the minimum amount of rupees needed for buying six pens, we can simply multiply the no of pens taken which is 6 by its least no cost and that is Rs 26 which will give the answer 156. Now we can multiply the no of pens taken which is 6 by its most no of cost and that is Rs 29 which will give the answer 174. Now we got the idea that the number should be between 156 and 174 so, we can simply get the answer 173 as it is the only number between 156 and 174.