To answer this question, the user needs to have knowledge about the characters in Shinchan's friends group.
Out of the given options, the character who is most intelligent in Shinchan's friends group is Kazama.
Option A: Nanny is not a part of the friends group and is not known for being particularly intelligent.
Option B: Masao is known for being kind, friendly and helpful, but not particularly intelligent.
Option C: Suzuki is known for being carefree and not particularly intelligent.
Option D: Kazama is known for being intelligent, studious, and the top student in their class.
Therefore, the correct answer is:
The Answer is: D. Kazama.