Find a Formula for A_n ?for the Arithmetic Sequence $\frac { 23 } { 4 }$

Multiple Choice

Find a formula for a_n ?for the arithmetic sequence. ?
A₁ = -5,a₅ = 18
?

A) a_n ?= $\frac { 23 } { 4 }$ n - $\frac { 43 } { 4 }$
B) a_n ?= $\frac { 23 } { 4 }$ n + 43
C) a_n ?= $\frac { 43 } { 4 }$ - 43n
D) a_n ?= $\frac { 43 } { 4 }$ + 43n
E) a_n ?= $\frac { 23 } { 4 }$ n + $\frac { 43 } { 4 }$