Recursive languages are a subset of:a.Recursively enumerable languagesb.Context-sensitive languagesc.Context-free languagesd.Regular languages

Recursive languages are a subset of Recursively enumerable languages.

Here's a step-by-step explanation:

1. Recursive languages: These are a type of formal language for which there exists a Turing machine that, when presented with any string over the alphabet of the language, halts and accepts if the string is in the language, and halts and rejects otherwise.

2. Recursively enumerable languages: These are a superset of recursive languages. A language is recursively enumerable (also known as semi-decidable, partially decidable, or Turing-recognizable) if there exists a Turing machine which will halt and accept for every string in the language. However, for strings not in the language, the Turing machine may either halt and reject, or run forever.

Therefore, every recursive language is also recursively enumerable, but the converse is not true. Hence, recursive languages are a subset of recursively enumerable languages.

On the other hand, context-sensitive languages, context-free languages, and regular languages are all subsets of recursive languages. Therefore, they are not the correct answer to your question.