(A): Material used in the construction of a standard resistance is constantan or manganin.
(R): Temperature coefficient of Resistance constantan is very small. 

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. 'A' is true and 'R' is false
D. 'A' is false and 'R' is false

Answer

A