A manufacturing plant needs to have a horn sound to signal quitting time. The horn should be activated when either of the following conditions is met:

1. It's after 5 o'clock and all machines are shut down.

2. It's Friday, the production run for the day is complete, and all machines are shut down. Design a logic circuit that will control the horn. (Hint: Use four logic input variables to represent the various conditions; for example, input A will be HIGH only when the time of day is 5 o'clock or later.)