Answer: D. conduction
Explanation:
Charge is transferred from one object together by mainly three methods:
1. Induction: when a charged object is brought close to an uncharged object, the charge is induced.
2. Friction: when two bodies having different electro-negativity are rubbed against each other, both of them get charged. For example, balloon when rubbed with fur.
3. Conduction: when a charged object is touched to an uncharged object, the uncharged object gets charged.
Thus, when a negatively charged rod touches a conductor, the conductor would be charged by conduction.