Correct option is D
· Let comes first.
· Lethal comes before Lethargy.
· Lethargy comes next.
· Letter comes after Let and Lethargy.
· Lest comes last.
Thus, the correct order is: 1 (Let), 4 (Lethal), 2 (Lethargy), 3 (Letter), 5 (Lest).
Correct answer: (d) 51423