Please help with this question, please! I don't understand it....

Answer:
The third option is correct: 5.7 units, M(7, 5, 2.5).
Step-by-step explanation:
The distance is √ [(9-5)^2 + (7-3)^2 + (3-2)^2 ]
= √ (16 + 16 + 1)
= √33
= 5.7.
The mid point = (9+5)/2 , (7+3)/2, (3+2)/2
= (7, 5, 2.5).