It has been to us that there are a total number of 220 people.
The box plot has been shown to us. We know that in a box plot from the Lower Quartile to the Median the data is 25% of the total amount of data. Likewise, from the Median to the Upper Quartile it is 25% again and from the Upper Quartile to the last data. It is again 25%.
Now, as per the box plot given to us, 6 hours is the Lower Quartile, therefore, more than 6 hours at the computer will have 25%+25%+25%=75% of the total people. The number of total people is 220. Therefore, the number of people who spend more than 6 hours at a computer will be:
75% of 220=

Thus, Option A is the correct option.