Trojans are . a. asteroids which fall to the Earth
b. long-period comets
c. planets with ring systems
d. asteroids affected by Jupiter's gravity

d. asteroids affected by Jupiter's gravity

Explanation:

A Trojan horse or Trojan is a type of malware that is often disguised as legitimate software. Trojans can be employed by cyber-thieves and hackers trying to gain access to users' systems. Users are typically tricked by some form of social engineering into loading and executing Trojans on their systems.

D

Explanation:

D is the correct answer, they are planets that are close to the center star