The answer is B: orange star.

The rule
The pattern repeats every 3 things: yellow star, orange star, orange star. 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 = ["yellow star", "orange star", "orange star"]
for position in range(8):
print(position + 1, pattern[position % len(pattern)])
When you run it, Python prints:
1 yellow star 2 orange star 3 orange star 4 yellow star 5 orange star 6 orange star 7 yellow star 8 orange 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!