Concept: The question tests on Word Problem and Analytical reasoning

Solution:
 

Given, Shawana reads 50 pages/day, and she will never begin the next book on the same day that she finishes the previous one.

1st book -253 pages= 50*6 =300 --->6 days (As there are 253 pages)

2nd book- 110 pages = 3*50=150---->3 days

3rd book-117 pages=3*50=150------->3 days

4th book-170 pages = 4*50=200------>4 days

5th book-155 pages = 4*50 = 200--->4 days

6th book-50 pages =1*50=50------>1 day

7th book-205 pages=5*50=250----->5 days

8th book-70 pages=2*50=100------->2 days

Total days = 6+3+3+4+4+1+5+2=28 days

 => 8 books would be completed in 28 days

(option b)