An exotic carp is
A. Cirrhinus mrigala
B. Cyprinus carpio
C. Labeo bata
D. Barbus stigma

Hint: Exotics carp or fish is an alien species that are non-indigenous having their origin in another country. Several exotic species have been introduced in the Indian waters. The use of exotic species for fisheries and aquaculture diversification has been practiced.

Complete answer:
Cyprinus carpio is an exotic carp species. This species is commonly called the common carp. It is a widespread freshwater fish of water lakes and large rivers in Europe and Asia. Common carp is a native of china. There are three varieties of common carp: Scale carp, Mirror carp and Leather carp.
There are many traits of exotic species:
> Fast growth.
> Tolerance of a wide range of environmental conditions.
> Rapid reproduction.
> Ability to live of a wide range of food types.
There are two mechanisms which help in the establishment of exotic species in a different or new environment. First mechanism which focuses on the exotic species and the second mechanism which focuses on the invaded ecosystems.
Some examples are Salmo gairdneri, O. niloticus and H. molitrix etc.
When an exotic species is parasite or disease free, they are transported to the natural environment.

So, the correct answer is option B.

Note: The first batch of exotic species was introduced by Maclvor in 1874 and in India it was introduced in 1959 at Cuttack.