4. (25 points) You are given the task of designing a logic circuit corresponding to the K-map below while keeping the cost at a minimum. Assume that a gate with n inputs costs $n. So, for instance, an inverter will cost $1, a 2-input AND gate will cost $2, a 3-input OR gate will cost $3, etc. Gates with inverted inputs will cost $1 extra for each inverted input. a, 6 00 01 11 10 c, d 00 1 1 01 1 1 11 1 1 10 1 1 (a) [15 points) Write the minimized Boolean equation corresponding to the Karnaugh map. (b) [5 points) Sketch the schematic for your circuit. (c) [5 points) What is the cost of your circuit