3. A computer user plans to purchase single-piece software and boxed disks, priced at 60 yuan and 70 yuan each, respectively, with a budget of no more than 500 yuan. According to the needs, the user must buy at least 3 pieces of software and at least 2 boxes of disks. The number of different purchasing options is
A. 5 options
B. 6 options
C. 7 options
D. 8 options
$7 y \leqslant 50$.
(1) When $x=3$, $y=2,3,4$. There are 3 ways to purchase. (2) When $x=4$, $y=2$, 3. There are 2 ways to purchase. (3) When $x=$ 5, $y=2$. There is 1 way to purchase, (4) When $x=6$, $y=2$, there is 1 way to purchase. In summary, there are 7 ways to purchase, so the answer is $\mathrm{C}$.
Note This problem tests the application of inequalities, modeling ability, classification and discussion ideas, and application awareness.