To solve the linear inequality \( Hy < 7 \) for \( y \), where \( H \) is a number greater than 0, we can isolate \( y \) by dividing both sides of the inequality by \( H \).
Starting with: \[ Hy < 7 \]
Now, divide both sides by \( H \): \[ y < \frac{7}{H} \]
Thus, the correct choice is: A. \( y < \frac{7}{H} \).