This question was previously asked in

VSSC (ISRO) Technician B (Electronic Mechanic) 2012 Official Paper (Held on 22 Dec 2012)

Option 4 : 1

**Concept:**

Name |
AND Form |
OR Form |

Identity law |
1.A=A |
0+A=A |

Null Law |
0.A=0 |
1+A=1 |

Idempotent Law |
A.A=A |
A+A=A |

Inverse Law |
AA’=0 |
A+A’=1 |

Commutative Law |
AB=BA |
A+B=B+A |

Associative Law |
(AB)C |
(A+B)+C = A+(B+C) |

Distributive Law |
A+BC=(A+B)(A+C) |
A(B+C)=AB+AC |

Absorption Law |
A(A+B)=A |
A+AB=A |

De Morgan’s Law |
(AB)’=A’+B’ |
(A+B)’=A’B’ |

**Analysis:**

Given:

Y = (1+A+B+C)

By using Null Law;

Y = 1

Hence, option 4 is correct.