Helen, a high school teacher, wants her students to actively participate more in class. She has decided to use reinforcement theory to get the required results. Which of the following methods is she most likely to use?

a)She is going to call on students who never participate.

b)She is going to yell at students, telling them that they are not making good grades.

c)She is going to ask the students that always participate to allow the others to have a chance.

d)She is going to model what active participation should look like, at the beginning of class.

e)She is going to give students extra credit each time that they contribute