To get the ratio p : q (for p q), one has to add a number to each term of the ratio x : y, the number is

• A. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>px + qy</center></td></tr><tr><td style="text-align: center;">p q</td></tr></table>
• B. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>qx py</center></td></tr><tr><td style="text-align: center;">p q</td></tr></table>
• C. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>px qy</center></td></tr><tr><td style="text-align: center;">p q</td></tr></table>
• D. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>py qx</center></td></tr><tr><td style="text-align: center;">p q</td></tr></table>