The correct option is B right
The Oxygen dissociation curve is a graph that plots the proportion of haemoglobin in its oxygen-laden saturated form on the vertical axis against the partial pressure of oxygen on the horizontal axis.
The Oxygen dissociation curve has a sigmoid shape because of the co-operative binding of oxygen to the haemoglobin.
The Oxygen dissociation curve can be shifted to the right or to the left by a variety of factors.
A decrease in the pH shifts the curve to the right, while, an increase in the pH shifts the curve to the left.