Answer:
The variable c represents the domain as it is the independent variable.
The domain of the function F(c) is given by c ≥ 0. 
So, only positive values for the input make sense. 
The upper limit of the domain is +∞ and lower limit is 0. 
It is not possible for the team to earn $50.50 as it will be only multiple of 2.
Step-by-step explanation:
If F(c) represents the earning of a volleyball team from selling c cupcakes and each cupcake costs $2 each, then the equation that models the situation is  
F(c) = 2c ..... (1)
The variable c represents the domain as it is the independent variable. (Answer)
The domain of the function F(c) is given by c ≥ 0. (Answer)
So, only positive values for the input make sense. (Answer)
The upper limit of the domain is +∞ and the lower limit is 0. (Answer)
It is not possible for the team to earn $50.50 as it will be only multiple of 2. (Answer)