单项选择题

　　Behavioral psychologists apprehend that conditioned fear responses to atone previously paired with a shock diminish, if the tone is repeatedly presented　without the shock, a process known as extinction. Since Parlor it has been hypothesized that this extinction does not erase conditioning, but forms a new memory. Research has now demonstrated that destruction of the infralimbic cortice blocks recall of fear extinction, indicating that it might store long-term extinction memory. Infralimbic neurons recorded during fear conditioning and extinction fire to the tone only when rats are recalling extinction on the following day, and rats indicating the least fear responses also demonstrate the greatest increase in infralimbic tone responses. Conditioned tones paired with brief electrical stimulation of infralimbic cortex elicit low fear responses in rats that have not undergone extinction. Thus, stimulation resembling extinction-induced infralimbic tone responses is able to simulate extinction memory.

It can be inferred that a rat with its infralimbic cortices destroyed would respond which of the following ways to a tone previously conditioned to induce a fear response（）
Ⅰ. It would demonstrate fear if extinction had occurred the previous day.
Ⅱ. It would demonstrate fear if extinction had occurred earlier than the previous day.
Ⅲ. It would demonstrate fear even if extinction had never occurred at all.

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