Question

which engine component is attached directly to the pistons
camshaft
head gasket
crankshaft
pushrods

Explanation:

The crankshaft is connected to the pistons via connecting rods. As the pistons move up and down (reciprocating motion), the connecting rods convert this linear motion into rotational motion of the crankshaft. The camshaft controls valve operation, the head gasket seals the cylinder head to the engine block, and pushrods (in some valvetrain designs) transfer motion from the camshaft to the valves. None of these (camshaft, head gasket, pushrods) are directly attached to the pistons like the crankshaft (via connecting rods) is.

Answer:

crankshaft