To stay abstinent, one should
a. practice refusal skills
b. practice avoidance techniques
c. set limits and stick to them
d. all of the above

In the question "To stay abstinent, one should" practice refusal skills, practice avoidance techniques and set limits and stick to them. Abstinence is the ability of a person or thing to refrain from an activity such as comsumption of alcohol and sex. Ability to refuse advances, ability to avoid some practices that may lead to indulging in the act you want to abstain from and setting limits for your self and sticking to them helps you to abstain from activities you want to abstain from.

The correct answer is C. produced naturally in short lengths

They are short and can be seen on a variety of different materials and can sometime even be made from mixtures of different materials. This is opposite of filament fibers such as pure silk or synthetic fibers which are very long and smooth. A common example of a stable fiber can be cotton which is seen as the small puffy thing.