The answer is D: blue hexagon.

The rule
The pattern repeats every 3 things: blue hexagon, blue hexagon, purple circle. Then it starts again from the beginning.
The pattern as Python code
Here is a tiny Python program that follows the same rule. Type it into IDLE and run it to print the whole pattern, including the answer.
pattern = ["blue hexagon", "blue hexagon", "purple circle"]
for position in range(8):
print(position + 1, pattern[position % len(pattern)])
When you run it, Python prints:
1 blue hexagon 2 blue hexagon 3 purple circle 4 blue hexagon 5 blue hexagon 6 purple circle 7 blue hexagon 8 blue hexagon
Pixel says: Try changing a number in the code and run it again. Can you make the pattern go on for 20 steps? Meow!