Howard decides to study the impact that ice cream has on fighting. In his study he learns that ice cream
is directly correlated to fighting, however once he
controls for temperature he learns that the correlation
disappears altogether. In this example ice cream was
the variable, fighting was the variable, and temperature
was the variable.

_independent, intervening, dependent
-intervening, dependent, independent
-independent, dependent, intervening
-dependent, independent, intervening

C. -independent, dependent, intervening

Explanation:

Independent variable is defined as the variable that can be changed during the experiment, dependent variable is the variable which is being tested and whose value depends on independent variable and intervening variable impacts the relationship between a dependent variable and an independent.

So, in the given study, ice cream was an independent variable as it can be changed during study and Howard wants to study its impact, fighting was a dependent variable as it is being tested and the temperature was the intervening variable as it is a cause of independent variable and also impacts the relationship between a dependent variable and an independent.

Hence, the correct option is C. independent, dependent, intervening.