Where in Himachal Pradesh Bee keeping was introduced as a source of livelihood?

The correct answer is: A. Kullu Valley

Beekeeping was introduced as a source of livelihood in the Kullu Valley in Himachal Pradesh in the early 1900s. The practice was brought to the region by the British, who were looking for ways to increase the production of honey. The Kullu Valley is a particularly good location for beekeeping, as it has a temperate climate and a variety of flowers that provide nectar for the bees. The practice has since become a popular source of income for many people in the region.

The other options are incorrect because:

• Spiti Valley is a high-altitude desert region that is not suitable for beekeeping.
• Solan is a city in the Indian state of Himachal Pradesh. It is not a major center of beekeeping.
• Nahan is a city in the Indian state of Himachal Pradesh. It is not a major center of beekeeping.