I NEED HELP ON THIS PROBLEM PLS

only A

Step-by-step explanation:

A is correct because if a number is less than 7, the number under the square root will be negative, and that will yield an imaginary (or non-real number)

B is incorrect because even if you choose a number less than 7, the result will still yield a real number

C is incorrect due to the same logic as B

D is incorrect because you can take the cube root of a negative number without it being non-real.

54

step-by-step explanation:

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons