While considering to build your dream house, you listed various costs involved as follows:

A$.$ The cost to buy a land plot available at RM $20$ per sq$.$ feet.

B$.$ The cost to demolish the existing structure on the plot at a cost of RM $22,000.$

C$.$ The consultancy fee of RM $20,000$ to be paid to the professional architect.

D$.$ The cost to build the house at RM $207$ per sq$.$ feet.

E$.$ You also wish to add a pool in the house if the budget allows.

Which are the fixed, variable, and incremental costs in the list above?