If $A B=Q R, B C=P R$ and $C A=P Q$, then
(A) $\triangle A B C \cong \triangle P Q R$
(B) $\triangle C B A \cong \triangle P R Q$
(C) $\triangle B A C \cong \triangle R P Q$
(D) $\triangle P Q R \cong \triangle B C A$
Solution: $AB = QR, BC =PR, CA = PQ$ (Given)
Triangles follow the SSS criterion for congruence
In option (A) $\triangle A B C \cong \triangle P Q R$, from this, we conclude that side $\mathrm{AB}=\mathrm{PQ}$
But it is given $A B=Q R$ and $A B=P Q$ may or may not be possible
In option (C) $\triangle B C A \cong \triangle R P Q$, by the same relation, we say that
side $B A=R P$ may or may not be possible because it is given $B A=Q P$
In option (D) $\triangle P Q R \cong \triangle B C A$
side $P Q=B C$ may or may not be possible
In option (B) $\triangle C B A \cong \triangle P Q R$,
$C B=P R, B A=R Q, A C=Q P$ (all are given.)
Hence option (B) is correct.