Let the circumference of the front wheel be \( C_1 \) and that of the rear wheel be \( C_2 \).
The total distance covered by each wheel is the same, given by:
\[ \text{Revolutions} \times \text{Circumference} = \text{Same Distance} \]
\[ 10 \times C_1 = 20 \times C_2 \]
Dividing both sides by \( 10C_2 \):
\[ \frac{C_1}{C_2} = \frac{20}{10} \]
\[ = 2:1 \]
Thus, the correct answer is 2:1 (Option A).