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Q. |
## Let L1 be a recursive language. Let L2 and L3 be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true? |

A. | L2-L1 is recursively enumerable |

B. | L1-L3 is recursively enumerable |

C. | L2 intersection L1 is recursively enumerable |

D. | L2 union L1 is recursively enumerable |

Answer» B. L1-L3 is recursively enumerable |

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