题干
根据表格内容，选择正确答案。
| First name IR | Last name as | Telephone number |
| Jack | Brown | 299-2321 |
| Eric | Smith | 551-1567 |
| Alice | Smith | 660-5117 |
| Linda | Green | 299-2312 |
根据表格内容，选择正确答案。
| First name IR | Last name as | Telephone number |
| Jack | Brown | 299-2321 |
| Eric | Smith | 551-1567 |
| Alice | Smith | 660-5117 |
| Linda | Green | 299-2312 |
，则z=2x-3y的最小值是（ ）