## Discussion Forum

Que. | For the set N of natural numbers and a binary operation f : N x N → N, an element z ∊ N is called an identity for f, if f (a, z) = a = f(z, a), for all a ∊ N. Which of the following binary operations have an identity? 1. f (x, y) = x + y - 3 2. f (x, y) = max(x, y) 3. f (x, y) = x^y |

a. | I and II only |

b. | II and III only |

c. | I and III only |

d. | None of these |

Answer:I and II only |