The expected answers were:

(a) The truth table for the logic circuit as is as shown below.

A |
B |
C |
F |

0 |
0 |
1 |
0 |

0 |
1 |
1 |
1 |

1 |
0 |
1 |
0 |

1 |
1 |
0 |
0 |

(b) The Boolean expression that relates the output to the input is

F = (A.B) . B = C.B

(c) As can be seen from the truth table, F is at the logic level 1 only when A = 0 and B = 1. The equation was on digital electronics. The question was popular with the candidates. Quite a few candidates gave more than four correct responses.