Among the following which one lays eggs and does not produce young ones directly?

The echidna is a monotreme — a group of egg-laying mammals that includes echidnas and the platypus — and thus lays eggs rather than giving birth to live young [1]. Kangaroos are marsupials that give birth to highly underdeveloped young which then continue development in a pouch, not by egg-laying [2]. Whales are cetacean mammals (not fish) and give birth to live calves after internal gestation [3]. Most mammals are viviparous (give birth to live young); monotremes are the notable exception among living mammals, laying leathery-shelled eggs [4]. Therefore, among the options provided, the echidna is the egg-layer.

Sources

1. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 12: Animal Diversity of India > L?..3,2, Marsupials > p. 190
2. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 9: Indian Biodiversity Diverse Landscape > Do you know? > p. 154
3. [4] https://en.wikipedia.org/wiki/Mammalian_reproduction