Design an 8-4-2-1 BCD code converter to drive a seven segment indicator. The four inputs to the converter circuit(A, B, C, and D) represent an 8-4-2-1 binary coded decimal digit. Assume that only input combinations representing 0-9 can occur as inputs, so that combinations 1010 through 1111 are don't cares. Design your circuit using two, three, and four input NAND gates and inverters. Try to minimize the number of gates required. The variables A, B, C, and D will be available from toggle switches.