The following figure represents time vs. learning curves of two students, Q and R for learning a Mathematics lesson : Which one of the following inferences can be drawn from the graph

(a)

R started slowly in the beginning but got ahead of Q to complete learning the lesson

(b)

Q started slowly and finished learning the lesson earlier than R

(c)

R was always faster than Q in learning Mathematics

(d)

Q was always faster than R in learning Mathematics