Task: Question Answering
Input (English): Problem: a swimmer can swim in still water at 4 km / h. if the speed of the water current is 1 km / h, how many hours will the swimmer take to swim against the current for 6 km ?
Options: a. 1.2, b. 1.4, c. 1.6, d. 1.8, e. 2
Output (English): e