4. A patient's pulse is measured three times. The results are 70 bmp, 80 bpm, and 120 bpm. The doctorwould like to find a number which most accurately represents the patient's pulse. To do so, they minimize:p(x) = (x70)2+ (x80)2+ (x120)2(a) Find all the critical points ofp(x).(b) Calculate which values ofxminimizesp(x).(c) Briefly explain why the doctor might choose this functionp(x) to minimize.