Select the option that is true regarding the following two statements labelled Assertion (A) and Reason (R).Assertion (A): Platinum and constantan are preferred materials used for fabricating rheostats.Reason(R): High resistivity, high working temperature, high corrosion resistance, low cost

• A. A is false but R is true
• B. Both A and R are true and R is the correct explanation of A
• C. Both A and R are true, but R is not a correct explanation of A
• D. A is true but R is false