Which of the following statements is true for operant conditioning?

A) Avoidance training is especially easy to extinguish.
B) The stronger the original learning, the harder it is to extinguish.
C) Complex behavior is easier to extinguish than simple behavior.
D) The greater the variety of settings in which learning takes place, the easier the behavior is to extinguish.

According to operant conditioning, the strength of the learned behavior determines how difficult it is to extinguish. The stronger the original learning, the harder it is to extinguish. Therefore, option B is the correct statement. Option A is incorrect because avoidance training can be difficult to extinguish due to the fear of punishment. Option C is incorrect because complex behavior is usually more resistant to extinction compared to simple behavior. Option D is incorrect because learning in multiple settings makes behavior more resistant to extinction.