Final answer:
The basal body has a structure similar to a centriole, consisting of nine microtubule triplets. It is not organized into a 9+2 array of microtubules, which is found in cilia and flagella, not basally.
Step-by-step explanation:
The structural organization of a basal body is most closely similar to a centriole, and it is organized into a ring of nine microtubule triplets. Basal bodies serve as the foundation for cilia and flagella, giving rise to a typical 9+2 arrangement of microtubules, which includes 9 outer doublets and 2 central microtubules when observed in cross-sections of these appendages.
The mention of an 'inner dynein arm' is in reference to the dynein motor proteins associated with the axoneme's microtubules, which are critical for the bending and motion of cilia and flagella, but these are not a structural component of the basal body itself. Therefore, the correct answer to the student's question is (3) An arrangement similar to a centriole.