A method for withdrawing a token system is:

A$.$

Gradually increase the number of responses required to earn a token.

B$.$

Gradually decrease the length of time the token economy is in effect.

C$.$

Gradually make more of activities and privileges used as backup items be those found in the untrained setting.

D$.$

Increase the price of desirable items and keep the price of undesirable items low.

E$.$

Gradually move from concrete tokens $($such as poker chips$)$ to something less visible $($such as a point card the learner carries with him$/$her$).$

F$.$

All of these are methods for withdrawing a token system.

G$.$

None of these methods should be used. Once implemented, a token system should not be withdrawn.