If We Were to Train Someone First to Put a Quarter

If we were to train someone first to put a quarter in the vending machine (1st link) , then to press the button of the drink they want (2^nd link) , then to approach the dispensed drink (3^rd link) , what would this entire training procedure be?

A) backward chaining
B) forward chaining
C) total-task presentation
D) dual-functioning chained stimulus
E) differential reinforcement of low rate
F) the first link last method