Which of the following is not an In situ conservation approach?

The correct answer is Option (3) → Cryopreservation

In situ conservation protects species in their natural habitat; ex situ conservation keeps them outside it.

Option (1) Biosphere reserves — An in situ conservation approach. Large natural areas are protected with the people living in them.

Option (2) National parks — An in situ conservation approach. Whole ecosystems are protected where they are.

Option (3) Cryopreservation — Not an in situ conservation approach. Gametes, embryos or seeds are kept at very low temperature (in liquid nitrogen at −196°C), far from their habitat: ex situ.

Option (4) Sacred groves — An in situ conservation approach. Forest patches protected by communities for religious reasons.

NCERT Extract:
How Do We Conserve Biodiversity? – “… In recent years ex situ conservation has advanced beyond keeping threatened species in enclosures. Now gametes of threatened species can be preserved in viable and fertile condition for long periods using cryopreservation techniques, eggs can be fertilised in vitro, and plants can be propagated using tissue culture methods.”
How Do We Conserve Biodiversity? – “… In India, ecologically unique and biodiversity-rich regions are legally protected as biosphere reserves, national parks and sanctuaries. India now has 14 biosphere reserves, 90 national parks and 448 wildlife sanctuaries.”