(c) : A spindle of fine fibres begins to develop during prophase. It consists of microtubules which are made of protein called tubulin and certain other associated proteins. These delicate fibres radiate from the centriole and constitute aster. This option was not given in the entrance paper. As actin and myosin are involved as contractile machinery in many nonmuscle cells so it can be considered as the correct answer. Myoglobin is present in muscles which can bind to oxygen.