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The right answer is B. The subject noun species is plural here (although the singular form is identical), and so the plural verb are is necessary. Furthermore, the correct idiom in English is are typical of; the phrase are usual of is simply not used.

The right answer is NOT A because the plural species and singular is do not agree.

The right answer is NOT C because the verb typify would not require the preposition of (although this would be correct if of were omitted).

The right answer is NOT D because are more usual of is simply not an idiom that occurs in English.