According to J.V. Narlikar which of the following has so far not been considered as a science?

Astrology is the answer. Narlikar's point is about method, not history or culture. Astrology makes predictions about human affairs from planetary positions, but its claims have not survived controlled, repeated testing. Narlikar, an astrophysicist, has argued that it fails the test of falsifiability that Karl Popper made central to science, and that its predictions do no better than chance in blind trials.

Why the others are sciences:

• Astronomy (B): the systematic study of celestial bodies using observation and physical law. Aryabhata's work is an early example of this method.
• Cosmology (C): the physics of the origin and evolution of the universe, tested against observations such as the cosmic microwave background.
• Nanotechnology (D): applied physics, chemistry and materials science working at the scale of 1 to 100 nanometres.

Core concept: the demarcation between science and pseudoscience. This connects to Article 51A(h), which asks citizens to develop scientific temper, a recurring Mains theme on rationality versus superstition.

Trap: aspirants see "Jyotish" in Indian heritage and assume astrology has the same scientific status as astronomy. In Narlikar's framework, it does not.