Which of the following statements are true?
(i) A body can have constant speed but varying velocity.
(ii) A body can have constant velocity but varying speed.
(iii) A body can have acceleration without having velocity.
(iv) A body can have velocity without having acceleration.

Speed is magnitude of velocity. If a body moves with velocity which has constant magnitude but direction can change as in uniform circular motion.Similarly a body can have acceleration without having velocity for example vertically projected body at its highest point. A body moving with constant velocity acceleration will be zero but if a body has variable speed its velocity automatically changes. so option i, iii and iv are correct.