Answer:
The correct explanation is option B;
B. ∠L ≅ ∠L By Reflexive Prop. ≅.
Since ║ , ∠LOP ≅ ∠LMN by the Corr. ∠s Post. Therefore, ΔLOP ~ ΔLMN by AA ~. OP = 2 and MN = 6
Explanation:
The given parameters are;
 = 5
 = 10
 = + = 15
 = x - 3
 = x + 1
A two column proof is presented as follows;
Statement Reason
∠L ≅ ∠L By Reflexive property of congruency
 ║ Given
∠LOP ≅ ∠LMN By the Corresponding angles Postulate
Therefore
ΔLOP ~ ΔLMN By AA similarity Postulate
Where we have that ΔLOP and ΔLMN, we get;
/ = / = 5/15 = 1/3
∴ (x - 3)/(x + 1) = 1/3
3·(x - 3) = 1·(x + 1)
3·x - 9 = x + 1
3·x - x = 1 + 9 = 10
2·x = 10
x = 10/2 = 5
x = 5
 = (x - 3) = 5 - 3 = 2
 = 2
 = x + 1 = 5 + 1 = 6
 = 6
Therefore, the correct option is ∠L ≅ ∠L By Reflexive Prop. ≅.
Since ║ , ∠LOP ≅ ∠LMN by the Corr. ∠s Post. Therefore, ΔLOP ~ ΔLMN by AA ~. OP = 2 and MN = 6.