A 50.0 mL sample of 0.436 M NH₄NO₃ is diluted with water to a total volume of 250.0 mL. What is the ammonium nitrate concentration in the resulting solution?

a. 0.459 M
b. 7.27 × 10⁻² M
c. 8.72 × 10⁻² M
d. 21.8 M
e. 2.18 × 10⁻² M