As a technician you are confronted with a TTL circuit board containing dozens of IC chips. You have taken several readings at numerous IC chips, but the readings are inconclusive because of their erratic nature. Of the possible faults listed, select

• A. An open input on the first IC chip on the board
• B. A solar bridge between the inputs on the first IC chip on the board
• C. none of these
• D. A defective IC chip that is drawing excessive current from the power supply