Dart combinations

This task is about finding all possible combinations.

darts and dartboard

In a game of darts, a total score is found by adding the scores of each dart together, e.g., 2 + 4 + 6 + 6 = 18.
 
a)
What is the lowest possible total score if three darts hit the target? __________
 
b)
If the total score from the three darts that hit the target was 16, what is the score of each dart?
 
___________          ___________          ___________
 
c)

 
Which of the following total scores are possible if all 4 darts hit the target?
Circle the four possible scores.

6          10          14          18          22          26