Which of the following is an assertion of ELM?

A) Most messages are processed through the central route.
B) Peripheral route processing is based on reflection.
C) Long-lasting change occurs through the peripheral route.
D) Central route processing is based on active thinking.

ELM asserts that central route processing involves active thinking and careful consideration of the message, while peripheral route processing relies on superficial cues and shortcuts. Therefore, option D is the correct assertion of ELM. Option A is incorrect because ELM posits that messages can be processed through either the central or peripheral route, depending on factors such as motivation and ability. Option B is incorrect because peripheral route processing is not based on reflection, but rather on quick, automatic judgments. Option C is also incorrect because lasting change is more likely to occur through the central route, which involves deeper processing and stronger attitudes.