For each answer, we can plug in the given points:
A) is technically the same as B), but B) expresses correct function notation.
B) 5 = 5(1) 
⇒ 5 = 5
     25 = 5(2) ⇒ 25 ≠ 10
     B) is incorrect.
C) I'm not sure what you mean y=5^5=x, but I'm going to use 

 because it's close to what you wrote:

The function 

 works for the points given.
D) 5 = 1 + 5 ⇒ 5 ≠ 6
     D) is not correct.
Please check your functions; I'm not sure that C) is a function.  In any case, the answer is C) because all the other answers are wrong.
 
        
        
        
The answer is #2 you’re welcome
 
        
             
        
        
        
Answer: B= A/(C+D)
Step-by-step explanation:
A = B(C+D)
Divide each side by B
A/B= C+D
Reciprocate both sides
B/A = 1/(C+D)
Now multiply each side by A
B = A/(C+D)