Which of the following is true regarding stress-strain curve of concrete?
a) A straight line up to the failure
b) Hyperbolic up to 0.002 strain value and then a straight line up to failure
c) Parabolic up to 0.002 strain value and then a straight line up to failure (Ans)
d) Straight line up to 0.002 strain value and then parabolic up to failure