Answer: LED have the lowest cost of operation.
Explanation:
If we ignore the initial procurement cost of the items the operational cost of any device consuming electricity is given by

Among the three item's LED consumes the lowest power to give the same level of brightness as compared to the other 2 item's thus LED's shall have the lowest operational cost.
Answer:
Circuit attached with explanation
Explanation:
Hi Dear,
A circuit is attached for your reference.
When you press "start" PB, the supply reaches the motor starter relay coil "M" that is also in parallel with the "start" PB which allows the motor to remain ON even when you release "start" PB as supply to relay coil is directly from supply "L" through "M".
To stop motor just press "stop" PB and the circuit breaks which de-energize the relay coil and the motor stops.
Hope this finds easy to you.
Answer:
B
Explanation:
Low beams should only be used when fog and rain is present, as high beams can cause a dangerous glare to you and other drivers. You should also use your fog lights, but not every vehicle has them.