#### Answer

Answer choice $F$: $a(n)=5+(nā1)(6)$

#### Work Step by Step

A function rule is written as $a(n) = a + (n-1)d$. $a$ is the first term, and $d$ is the common difference. The first term is $6$, and the common difference is $5$. Substitute these terms in.
$\boxed{a(n) = 5 + (n-1)6}$
The answer is $\boxed{F}$