Apply the nearest neighbour (NN) heuristic to the example below by calculating all the possible various routes to provide the most efficient route for the collection vehicle. (15) According to Krajewski and Malhotra (2022: 636), "A second way to improve energy efficiency involving transportation distances is route planning, which seeks to find the shortest route to deliver a service or product. Once the design of the supply chain has been determined, attention turns to minimising the distance travelled to supply the service or product to customers on a daily basis. They continue by noting that the nearest neighbour (NN) heuristic is a technique that creates a route by deciding the next city to visit on the basis of its proximity" Pick it Up, Ltd. collects used motor oil from several collection sites around the Johannesburg area. To minimise the use, and thereby the cost of its labour, vehicle, and energy resources, the company is interested in locating the shortest route that will allow its collection vehicle to visit each collection site exactly once. The table below provides the travel distances in kilometres between each site. Note that the company's recycling facility is located at site A.

From / to	a	b	c	d	e	f
A (depot)	-	25	50	48	41	60
B	25	-	35	22	23	43
C	50	35	-	25	47	65
D	48	22	25	-	24	40
E	41	23	47	24	-	21
F	60	43	65	40	21	-