The circuit functions as a sequential combination lock. To operate the lock, proceed as follows:1. Momentarily activate the RESET switch.2. Set the switches SWA, SWB, and SWC to the first part of the combination. Then momentarily toggle the ENTER switch back andforth.3. Set the switches to the second part of the combination, and toggle ENTER again. This should produce a HIGH at Q2 to open the lock. If the incorrect combination is entered in either step, the operator must start the sequence over. Analyze the circuit and determinethe correct sequence of combinations that will open the lock. b) When the combination lock is tested, it is found that entering the correct combination does not open the lock. A logic probe check shows that entering the correct first combination sets Q1 HIGH, butentering the correct second combination produces only a momentary pulse at Q2. Consider each of the following faults and indicate which one(s) could produce the observed operation. Explain each choice.(a) Switch bounce at SWA, SWB, or SWC.(b) CLR input of Q2 is open.(c) Connection from NAND gate 4 output to NAND gate 3 input is o