Multi-choice problem: Continue writing the next sentence in this paragraph:

How to improve your 5 k race time
Engage in hill training.
Hill training is a form of training where you run up and down hill. This can help build endurance and muscle, resulting in faster speeds.

Pick from:
a). Use your 10 k training sessions to improve endurance. Mountain cycling is a variation of hill training that uses the long distance bike..
b). Also, you may encounter a hill during a 5k, so hill training can help you prepare. Find a steep hill in a safe area near you..
c). Additionally, it helps you identify which road to use more easily. Contrary to popular belief, hill classes increase the quality of your fitness..
d). Hill training will also give you the flexibility to engage in high-altitude races. Aim for a healthy weight loss diet..
b).