Which of these is a complicated machine?

A. a nail

B. a pencil

C. a spoon

D. a car

D

Explanation:

Cuase is a car-

A car

Explanation;

A car runs on multiple complicated objects, that aren't simply fixed or made by anybody,

a nail wether it's a nail from the hand or nail to hammer, they're neither ran as a machine, that wouldn't be possible-

A pen isn't a machine but I would understand if you got stuck on that one,

A spoon, in no way shape or form is a complicated machine, or even a regular machine in general.

So your answer is car.