Find a Formula for A_n for the Arithmetic Sequence $\frac { 14 } { 3 }$

Multiple Choice

Find a formula for a_n for the arithmetic sequence.
A₁ = 8, a₄ = 18

A) a_n = $\frac { 14 } { 3 }$ + 14n
B) a_n = $\frac { 14 } { 3 }$ - 14n
C) a_n = $\frac { 10 } { 3 }$ n - $\frac { 14 } { 3 }$
D) a_n = $\frac { 10 } { 3 }$ n + 14
E) a_n = $\frac { 10 } { 3 }$ n + $\frac { 14 } { 3 }$