The numbers x, y and z are respectively proportional to 2, 3 and 5 and the sum of x, y and z is 80. If the number z is given by the equation z = ax 8, then a is

• A. 6
• B. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>3</center></td></tr><tr><td style="text-align: center;">2</td></tr></table>
• C. 3
• D. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>5</center></td></tr><tr><td style="text-align: center;">2</td></tr></table>