How is a worm different from a Trojan?

A$.$ A worm reproduces itself on the same computer, whereas a Trojan attempts to spread through the network.

B$.$ A worm gathers information and transmits to a server, whereas a Trojan hides and then spreads through a network.

C$.$ A worm spreads through a network, whereas a Trojan hides inside another program.

D$.$ A worm prevents a device from functioning until a ransom is paid, whereas a Trojan gathers information and transmits it to another device.