Psychological researcher walter mischel gave preschoolers a choice between one marshmallow now or two marshmallows when he returned a few minutes later. children who chose to wait for two marshmallows demonstrated
a) a pruning process. b) formal operational thinking. c) delay of gratification. d) postconventional morality.

.c) delay of gratification

Explanation:

Delay of gratification occurs when one is able to stop themselves from taking the presently available reward with hope that they will be getting a much more valued one in the future; one avoids enjoying a minor reward in order to wait for something bigger and better.

This teaches an individual as sense of self control.

This research has been crucial in showing how vital is to wait sometimes for something better and how children can be taught about waiting.

Children who are able to engage in delayed gratification at a younger age are likely to grow up and be more academically successful because they have learnt to always not take whatever is available at that moment but to wait for something bigger and better.

They have learnt self regulation.

As a result they are also less likely to engage in deviant behavior because instead of stressing out about things not going right now or rushing to get rewards they value the waiting process or delay gratification knowing something better will eventually come.

a photo collage of women at work during world war 2