1. **State the problem:** We need to find which collection has $\frac{2}{3}$ of the circles colored black. 2. **Understand the total circles:** Each collection has 6 circles (2 rows \times 3 columns). 3. **Calculate $\frac{2}{3}$ of total circles:** $$\frac{2}{3} \times 6 = 4$$ 4. **Check each collection's black circles:** - A: 1 black circle (not equal to 4) - B: 3 black circles (not equal to 4) - C: 4 black circles (equals 4) - D: 5 black circles (not equal to 4) 5. **Conclusion:** Collection C has $\frac{2}{3}$ of the circles black. **Final answer:** Collection C