Find the Mode(s)for the Given Sample Data Find the Mode of the Blood Types

Find the mode(s) for the given sample data.
-The blood types for 30 people who agreed to participate in a medical study were as follows. $\begin{array}{llllllllll}\mathrm{O} & \mathrm{A} & \mathrm{A} & \mathrm{O} & \mathrm{A} & \mathrm{AB} & \mathrm{O} & \mathrm{B} & \mathrm{A} & \mathrm{O} \\\mathrm{A} & \mathrm{O} & \mathrm{A} & \mathrm{B} & \mathrm{O} & \mathrm{O} & \mathrm{O} & \mathrm{AB} & \mathrm{A} & \mathrm{A} \\\mathrm{A} & \mathrm{B} & \mathrm{O} & \mathrm{A} & \mathrm{A} & \mathrm{O} & \mathrm{O} & \mathrm{B} & \mathrm{O} & \mathrm{O}\end{array}$

Find the mode of the blood types.

A) 13
B) $\mathrm { A }$
C) $\mathrm { O } , \mathrm { A }$
D) $\mathrm { O }$