To go from the equation \( 2x + 7y = 14 \) to the equivalent equation \( 4x + 14y = 28 \), you should multiply the entire equation \( 2x + 7y = 14 \) by 2.
So, \( 2 \cdot (2x + 7y) = 2 \cdot 14 \) gives you:
\[ 4x + 14y = 28. \]
The correct answer is 2.