To answer this question, you need to understand the size of Einstein's brain in relation to the average.
Option A) Bigger than average - This option is incorrect because Einstein's brain was not bigger than average.
Option B) Average - This option is incorrect because Einstein's brain was not average in size.
Option C) Normal - This option is incorrect because Einstein's brain was not considered normal in size.
Option D) Smaller than average - This option is correct because Einstein's brain was actually smaller than average. Studies conducted on Einstein's preserved brain after his death showed that it was smaller than the average human brain.
The correct answer is D. This option is correct because Einstein's brain was smaller than average.