Answer:
A. Face
Explanation:
A poppet valve some time called mash room valve.The word poppet shares etymology with "puppet". In past "puppet valve" was synonym for poppet valve. however, this usage of "puppet" is now obsolete. The valve stem moves up and down inside the passage called guide, which is fitted in the engine-block. the head of the valve called valve face, is generally ground to a 45 degree angle. So as to fit properly on the valve seat in the block and prevent leakage.
