Its a 2-d array with 2 rows and 4 columns per row.
Now if you arrange them in the array then
Row 0 will have :- 1,2,3,4
Row 1 will have:- 5,6,7,8
4 is in row 0 and its column its 3,as default in c language array starts from location 0.
So answer will be a[0][3],b will be answer here.had they given array starts from row=1 and col=1,then answer be a[1][4] i.e a.
As nothing is given here,assume starting from 0,0 as in c language,so b is correct option here.