Final answer:
The positive integers that are perfect squares and factors of 10 are 1 and 4.
Step-by-step explanation:
Perfect squares that are factors of 10:
To find the perfect squares that are factors of 10, we need to look for the positive integers that can divide 10 and are perfect squares.
The factors of 10 are 1, 2, 5, and 10. The perfect squares among these factors are 1 and 4. So, the positive integers that are perfect squares and factors of 10 are 1 and 4.
Therefore, the correct answer is d) 6.