UPSC Civil Service Exam Questions - Engineering

Q1:

Which one of the following is correct in respect of the influence line for the bending moment at one-fourths of the span from left support of a prismatic beam simply supported at ends ?

A It is composed of straight lines only

B It is composed of curved lines only

C It is composed of straight and curved line

D It is parabolic

ANS:A - It is composed of straight lines only

Why can't be a parabolic and hyperbolic also?