Answer: C
In triangle \( \triangle ABC \), DE is parallel to BC. ∴ \( \frac{AD}{AB} = \frac{DE}{BC} \) Or, \( \frac{AB - BD}{AB} = \frac{DE}{BC} \) Or, \( \frac{20 - 14}{20} = \frac{DE}{BC} \) Or, \( \frac{DE}{BC} = \frac{6}{20} = \frac{3}{10} \) ∴ \( DE : BC = 3 : 10 \)
In triangle \( \triangle ABC \), DE is parallel to BC. ∴ \( \frac{AD}{AB} = \frac{DE}{BC} \) Or, \( \frac{AB - BD}{AB} = \frac{DE}{BC} \) Or, \( \frac{20 - 14}{20} = \frac{DE}{BC} \) Or, \( \frac{DE}{BC} = \frac{6}{20} = \frac{3}{10} \) ∴ \( DE : BC = 3 : 10 \)