Is the triangle formed by joining the points A (1, 9), B (7, 1), and C (−5, 1) isosceles? Justify your answer.

A. Yes. AB=(1−1)2+(9−7)2−−−−−−−−−−−−−−−√; BC=(7−5)2+(1−1)2−−−−−−−−−−−−−−−√

B. Yes. AB=(1−7)2+(9−1)2−−−−−−−−−−−−−−−√; CA=(−5−1)2+(1−9)2−−−−−−−−−−−−−−−−√

C. No. BC=(7+5)2+(1−1)2−−−−−−−−−−−−−−−√; CA=(−5−1)2+(1−9)2−−−−−−−−−−−−−−−−√

D. No. BC=(7−5)2+(1−1)2−−−−−−−−−−−−−−−√; CA=(−5−1)2+(1−9)2−−−−−−−−−−−−−−−−√