Answer: (b) exactly one plane contains a given line and a point not on the line.
Step-by-step explanation: The basic postulates of geometry are very-well known to all of us. For example-
(i) The intersection of two lines determines a point,
(ii) Two parallel lines give result to a plane,
(iii) A line and a point not on the line determines a plane, etc...
Thus, with the help of the third point, we can easily arrive at the conclusion that a given line and a point not lying on the line is contained in a plane. For example- see the attached figure, AB is a line and P is any point not on the line. They both contained in the plane ABC.
Hence, the correct option is (b).