Figure shows three vectors $\overrightarrow{\mathrm{a}},\overrightarrow{\mathrm{b}} \mathrm{and} \overrightarrow{\mathrm{c}},$, where R is the midpoint of PQ. Then which of the following relations is correct?

$In ∆OPR, \overrightarrow{c}=\overrightarrow{a}+\overrightarrow{PR }......... \left(1\right)$

$In ∆ORQ, \overrightarrow{c}=\overrightarrow{b}-\overrightarrow{RQ} ..........\left(2\right)$

A/C to the question,  $\overrightarrow{PR}=\overrightarrow{RQ} .......\left(3\right)$

from (1), (2) and (3), $2\overrightarrow{c}=\overrightarrow{a}+\overrightarrow{b}$