6.下列函数是一次函数的是( )
0 282667 282675 282681 282685 282691 282693 282697 282703 282705 282711 282717 282721 282723 282727 282733 282735 282741 282745 282747 282751 282753 282757 282759 282761 282762 282763 282765 282766 282767 282769 282771 282775 282777 282781 282783 282787 282793 282795 282801 282805 282807 282811 282817 282823 282825 282831 282835 282837 282843 282847 282853 282861 366461
| A. | y=kx+2 | B. | y=-$\frac{6}{x}$ | C. | y=-3x2+2 | D. | y=-$\frac{x}{4}$ |