The letters of each proposed conguency statement need to be in corresponding positions of the original congruency statement
For example, consider the first answer selection. The letters on the left (CBA) are the 3rd, 2nd, and 1st letters of the original congruency statement. The letters on the right (MNL) are the 2nd, 3rd, and 1st letters of the original. The order 321 is not the same as the order 231, so the first choice is incorrect.
Appropriate choices are
∆BAC ≅ ∆MLN . . . . 3rd choice
∆ACB ≅ ∆LNM . . . . 4th choice
