(A) : Invar is used in metal tapes, balance wheels and pendulum clocks.
( R) : The coefficient of linear expansion of invar is very low.

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 but (R) is false
D. Both (A) and (R) are false

Answer

A