Assertion (A) : Manganin or constantin are used for making standard resistances. Reason (R) : Their resistivity is high while temperature coefficient is low.

Both (A) and (R) are true and (R) is the correct explanation of (A).   Both (A) and (R) are true but(R) is NOT the correct explanation of (A).   (A) is true but (R) is false. Both (A) and (R) are false.

Both (A) and (R) are true and (R) is the correct explanation of (A).

Manganin or constantin are used for making standard resistances because their resistivity is high while temperature coefficient is low.