1. **Stating the problem:** We are given multiple expressions for concentration functions $C(t)$ involving $t \geq 0$ and need to analyze or compare them. 2. **Listing the expressions:** - A: $\frac{1}{20} + \frac{1}{5}t$ - B: $\frac{7}{110}t$ - C: $\frac{5 + 2t}{100}$ - D: $\frac{5 + 2t}{100 + 10t}$ 3. **Understanding the expressions:** - A is a linear function with a constant term. - B is a linear function passing through the origin. - C is a linear function scaled by 100. - D is a rational function with both numerator and denominator depending on $t$. 4. **Simplify and compare:** - Expression A: $C(t) = \frac{1}{20} + \frac{1}{5}t = 0.05 + 0.2t$ - Expression B: $C(t) = \frac{7}{110}t \approx 0.0636t$ - Expression C: $C(t) = \frac{5 + 2t}{100} = 0.05 + 0.02t$ - Expression D: $C(t) = \frac{5 + 2t}{100 + 10t}$ 5. **Analyze behavior of D:** For large $t$, $C(t) \approx \frac{2t}{10t} = 0.2$ (approaches a horizontal asymptote). At $t=0$, $C(0) = \frac{5}{100} = 0.05$. 6. **Summary:** - A and C start at 0.05 but A grows faster. - B starts at 0 and grows linearly. - D starts at 0.05 and approaches 0.2 asymptotically. This analysis helps identify which graph corresponds to which expression based on intercepts and growth behavior.