The coastal district of Karnataka famous for its beaches and cashew nuts:

Udupi
Dakshina Kannada
Uttara Kannada
Kodagu

The correct answer is B. Dakshina Kannada.

Dakshina Kannada is a coastal district in the Indian state of Karnataka. It is located in the southwestern part of the state, on the Arabian Sea coast. The district is bordered by Udupi district to the north, Uttara Kannada district to the east, and Kerala state to the south. The Arabian Sea lies to the west.

Dakshina Kannada is a popular tourist destination, known for its beaches, temples, and wildlife sanctuaries. The district is also home to a number of industries, including agriculture, cashew processing, and tourism.

The district headquarters is Mangalore, which is the second largest city in Karnataka. Other major towns in the district include Udupi, Karkala, Puttur, and Sullia.

The district is divided into 13 taluks: Mangalore, Bantwal, Puttur, Sullia, Belthangady, Moodbidri, Mangalore North, Mangalore South, Ullal, Kinnigoli, Kasaragod, and Dharmasthala.

The district has a population of over 2.5 million people. The majority of the population is Hindu, followed by Muslims and Christians. The official language of the district is Kannada.

The climate of Dakshina Kannada is tropical. The average temperature ranges from 25°C to 30°C. The monsoon season is from June to September.

The district is home to a number of tourist attractions, including the beaches of Mangalore, Udupi, and Murudeshwara; the temples of Mangalore, Udupi, and Dharmasthala; and the wildlife sanctuaries of Dandeli and Nagarhole.

The district is also home to a number of industries, including agriculture, cashew processing, and tourism. The main agricultural products of the district are rice, coconut, and cashew nuts. The main industries of the district are cashew processing, textiles, and tourism.

Dakshina Kannada is a beautiful and diverse district with a rich history and culture. It is a popular tourist destination and a major economic hub of Karnataka.