The correct option is B slow paced, sustained work
Some muscle fibres have a very less amount of oxygen-storing pigments called myoglobin. Muscles rich in such fibres are called white muscles because of the pale or whitish appearance owing to the lack of the red myoglobin molecules. They also contain less number of mitochondria. They depend mostly upon anaerobic respiration for energy. These muscles are involved in short duration and fast paced work such as the movement of eyeballs.
On the other hand, red muscle fibres have high concentrations of myoglobin and more number of mitochondria. These help in aerobic respiration for prolonged periods of time, which can support slow paced and sustained work or exercise.