Question 11 (0.5 points) Which of the following statements is true? All product costs are variable costs. Some product costs are variable costs, and some product costs are fixed costs. All product costs are fixed costs. All period costs are variable costs. Question 12 (0.5 points) Which of the following statements is true? All product costs are fixed costs. All period costs are variable costs. Some period costs are variable costs, and some period costs are fixed costs. All period costs are fixed costs