Assertion (A) : $B{F}_3$  is non polar while $P{F}_3$  is polar
Reason (R) : ${\text{BF}}_3$  is trigonal planar whereas ${\text{PF}}_3$  is pyramidal in shape

If both A and R are true and R is the correct explanation of A 

If A is true but R is false

If both A and R are false

If both A and R are true but R is not the correct explanation of A