■ PROBLEM: An LED is lit (f=1) when the combination of four switches represents an unsigned integer that is odd and prime, where '1' represents the ON position of a switch and '0' the OFF position. For example: if abcd=1010→f=0. If abcd=0111 → f=1. ✓ Complete the truth table for this circuit: a b c d f 0 0 0 0 0 0 0 1 0 0 1 0 ✓ Derive (simplify if possible) the Boolean expression: f = 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 0 0 0 1 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1