Assertion (A) : If argument of ${\mathrm{z}}_1=\mathrm{\pi }/3,$ argument of ${\mathrm{z}}_2=\mathrm{\pi }/4$ then argument of ${\mathrm{z}}_1{\mathrm{z}}_2$ is $7\mathrm{\pi }/12$

Reason (R) : $\mathrm{Arg} \left({\mathrm{z}}_1{\mathrm{z}}_2\right)=\mathrm{Arg} {\mathrm{z}}_1+\mathrm{Arg} {\mathrm{z}}_2$

Both A and R are true but R is not correct explanation to A

A is true R is false

A is false R is true

Both A and R are true R is correct explanation to A