A swimmer travels from the south end to the north end of a 30.0 m pool in 15.0 s and makes the return trip to the starting position in 19.0 s. What is the average velocity for the second half of the swim?

A1.60 m/s to the south

C1.60 m/s to the north

B2.0 m/s to the north

D2.0 m/s to the south