Systematic desensitization involves
select one:
a. associating a pleasant relaxed state with anxiety-arousing stimuli.
b. depriving a client access to an addictive drug.
c. replacing a positive response to a harmful stimulus with a negative response.
d. associating unwanted behaviors with unpleasant experiences.

A. associating a pleasant relaxed state with anxiety-arousing stimuli.

Explanation:

Systematic desensitization is a type of technique used in cognitive therapy and it is based on the principle of classical conditioning.

The goal of this technique is to remove a phobia or a stimuli that causes anxiety and substitute it with a relaxation response.

This technique has three phases:

Therefore, we can see that systematic desensitization involves a relaxed state that will be associated with anxiety-arousing stimuli and that will help to get rid of the anxiety. Thus, the correct answer is A. associating a pleasant relaxed state with anxiety-arousing stimuli.

there is an explationation of this on a site called crash   course world history 1

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals