Question

spark plugs either use a ______ design or a washer type of gasket to form a seal between the spark plug and the cylinder head.

a. combustion
b. rough
c. smooth
d. taper

Explanation:

To solve this, we analyze the options based on spark plug gasket design knowledge. Spark plugs use either a taper design or a washer - type gasket for sealing with the cylinder head. “Combustion” relates to the engine's burning process, not the gasket design. “Rough” and “Smooth” don't describe the typical sealing design for spark plugs. Only “Taper” is a recognized design for this sealing purpose.

Answer:

d. Taper