Let's begin by listing out the information given to us:
There are four students: n = 4
Number of students to be selected: r = 2
To calculate the combination of 2 students to be chosen, we use:

Therefore, there 12 possible combinations from these
The answer is B.) one
Hope this helps :)
Answer:
The midpoint is (2,0)
Step-by-step explanation:
To find the x coordinate of the midpoint, add the x coordinates of the endpoint and divide by 2
(5+-1)/2 =4/2 =2
To find the y coordinate of the midpoint, add the y coordinates of the endpoint and divide by 2
(6+-6)/2 =0/2 =0
The midpoint is (2,0)
The answer to the question they gave you is D