Write the First Five Terms of the Sequence Defined Recursively $n$

Multiple Choice

Write the first five terms of the sequence defined recursively. Use the pattern to write the $n$ th term of the sequence as a function of $n$ . (Assume that $n$ begins with 1.)
$$a _ { 1 } = 21 , a _ { k + 1 } = a _ { k } - 5$$

A) $a _ { n } = 26 - 5 n$
B) $a _ { n } = 21 - 5 n$
C) $a _ { n } = 31 - 5 n$
D) $a _ { n } = 26$
E) $\quad a _ { n } = 21 ( n - 1 )$