Answer:
Conventional.
Explanation:
Kohlberg did some studies on morality and proposed a theory on moral development.
Kohlberg defined three different levels of morality (and each level consists in 2 stages). These levels are:
In the preconventional level, the person's morality is externally controlled and therefore acts based on what the punishment will be (1st stage) or based on how good will it be for him/her to act in some way (2nd stage)
The conventional level stages also have to to with external controls but now the person thinks in function of ensure positive relationships and societal order. The third stage here depends on the approval of others. The fourth stage has to do with accepting rules because they preserve the society order and functioning.
The postconventional level stages are defined in more abstract principles or values. The 5th stage sees the world as a place with different values that must be respected. Finally the 6th stage is based in universal ethical abstract principles.
In this example, Heather decides not to tell the teacher that her classmate Joshua is cheating on the math exam because she is afraid the other kids will call her a snitch. We can see that her focus has to do with external controls, in particular she is acting this way because she doesn't want to lose the approval of others. Therefore, we can say that she is in the Conventional stage of moral development.