The answer is C: blue heart.

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