Single/multi-choice problem: Which of the following solutions is better for the following goal:
How to Avoid Ingrown Toenails

OPT: [+] One of the main causes of ingrown toenails is trimming them too short.; [+] One of the main causes of ingrown toenails is not trimming them short enough.;
One of the main causes of ingrown toenails is trimming them too short.