Which of the Following Best Describes the Concept of Marginal

Which of the following best describes the concept of marginal probability?

A) It is a measure of the likelihood that a particular event will occur, regardless of whether another event occurs.
B) It is a measure of the likelihood that a particular event will occur, given the fact that another event has already occurred or is certain to occur.
C) It is a measure of the likelihood of the simultaneous occurrence of two or more events.
D) It is a direct way for defining the sample space of an experiment.
It is measure of the likelihood that either one or the other out of a possible two events will occur.