Solve the Problem $a _ { n } = 31 - 3 n ; 11$

Solve the problem.
-A triangular display of cereal boxes in a supermarket has 28 boxes in the bottom row, 25 boxes in the next row, and so on, in an arithmetic sequence. Find the general term for the sequence and how many rows there are in the display.

A) $a _ { n } = 31 - 3 n ; 11$ rows in the display
B) $a _ { n } = 28 - 3 n ; 9$ rows in the display
C) $a _ { n } = 31 - 3 n$ ; 10 rows in the display
D) $a _ { n } = 28 - 3 n$ ; 8 rows in the display