Human body works in the pH range of :

The human body maintains a tightly regulated blood pH in the range of approximately 7.35 to 7.45, which is slightly alkaline. Among the given options, 6.8 – 7.2 is the closest range that encompasses the physiological pH near neutrality at which most body enzymes and biochemical processes function. Deviations beyond this range cause acidosis (below 7.35) or alkalosis (above 7.45), both potentially life-threatening conditions. Buffer systems like bicarbonate, phosphate, and proteins maintain this narrow pH range.