(a) Compare the structures of ROM, PLA and PAL (6Marks) (b) A greenhouse is equipped with three sensors to measure the temperature, humidity and the soil moisture level. Each of these sensors produce a binary output to denote whether the measurement is above a threshold (logical 1) or not (logical 0). There is a fan and an air conditioner (ac) to perform the climate control inside the green house. Let us denote the "on" by logical1 and "off by logical 0 for these two control devices. The control should adhere to the following rules If the temperature or the humidity is high, at least one of the two control devices should be "on" If soil moisture is low, ac should be kept "off whatever the other sensor outputs are You are required to design a combinational logic circuit for the control function. i. State the truth table. (4Marks) i. Use a Karnough map to produce a simplified Boolean expression. (4Marks) (6Marks) ii Produce the logic circuit with a PLD