A characteristic of the soils in Nagaland is:

The correct answer is: a) High acidity.

The soils in Nagaland are highly acidic, with a pH of 4.5 or less. This is due to the presence of large amounts of organic matter in the soil, which releases acids as it decomposes. The acidity of the soil can make it difficult for plants to grow, as they require a more neutral pH to thrive. However, some plants, such as rhododendrons and blueberries, are adapted to acidic soils and can grow well in Nagaland.

Option b) is incorrect because the soils in Nagaland are not highly alkaline. Option c) is incorrect because the soils in Nagaland are not neutral pH. Option d) is incorrect because the soils in Nagaland are not high salinity.