A scientist uses a counter to determine the radioactivity of a nitrogen-13 sample. The sample of nitrogen-13 and the counter are placed on a laboratory table. The counter reading is noted over a time interval of $80\ \text{min}$, and the results are plotted on a graph. This graph shows count rate ($\text{counts min}^{-1}$) against time ($\text{min}$). What is the best estimate of the half-life of the nitrogen-13 sample?
- A$10\ \text{min}$
- B$12\ \text{min}$
- C$14\ \text{min}$
- D$40\ \text{min}$