The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Clearly by looking at equation it is distance between point (5,−4)
and circle y=√−3+4x−x2 or (x−2)2+y2=1
Assume p is distance between centre of circle (2,0) and the point (5,-4)
⇒p=√(5−2)2+(−4−0)2=5
Hence maximum distance is =5+1=6
⇒(√−3+4x−x2+4)2+(x−5)2=36
Thus the assertion is correct,
Reason is also explaining same thing, Therefore option 'A' is correct.