Find the Unit Rate $\frac { 4 } { 3 } \mathrm { in } . / \mathrm { hr }$

Find the unit rate.
-6 inches of rain after 8 hours

A) $\frac { 4 } { 3 } \mathrm { in } . / \mathrm { hr }$
B) $\frac { 6 } { 8 } \mathrm { in } . / \mathrm { hr }$
C) $\frac { 3 } { 4 } \mathrm { in } . / \mathrm { hr }$
D) $\frac { 3 } { 8 } \mathrm { in } . / \mathrm { hr }$