Find a Formula For $a _ { n }$ For the Arithmetic Sequence

Multiple Choice

Find a formula for $a _ { n }$ for the arithmetic sequence.
$$a _ { 3 } = 19 , a _ { 13 } = 99$$

A) $a _ { n } = 3 + 8 n$
B) $a _ { n } = 5 + 3 n$
C) $a _ { n } = 8 + 3 n$
D) $a _ { n } = 3 ( 8 ) ^ { n }$
E) $a _ { n } = - 5 + 8 n$