Which of the followings is/are true pertaining to the marginal rate of substitution (MRS) of two given below:

A. MRS is the rate at which consumer substitutes one good for the other

B. MRS falls as we move down the indifference curve from left to right.

C. An indifference curve is convex, if the MIS increases along the curve.

D. If MRS along the IC remains constant, then the IC is a straight line.

E. If MRS for two goods is zero or infinite, IC are shaped as right angles.

Choose the most appropriate answer from the options given below: