The correct answer is C. Intruding objects are younger in the law of inclusion.
In relative dating, the law of inclusion states that any rock fragments (inclusions) within another rock must be older than the rock that contains them. Conversely, the law of cross-cutting relationships states that a rock or fault that cuts through another rock must be younger than the rock it cuts through. Hence, intruding objects (like igneous dikes) that cut through existing rocks are considered younger than those rocks.