The answer is B: blue star.

The rule
The pattern repeats every 3 things: blue star, blue star, teal diamond. 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 star", "blue star", "teal diamond"]
for position in range(8):
print(position + 1, pattern[position % len(pattern)])
When you run it, Python prints:
1 blue star 2 blue star 3 teal diamond 4 blue star 5 blue star 6 teal diamond 7 blue star 8 blue star
Pixel says: Try changing a number in the code and run it again. Can you make the pattern go on for 20 steps? Meow!