抛物线y=ax2+bx+c上部分点的横坐标x,纵坐标y的对应值如表所示.给出下列说法:①抛物线与y轴的交点为(0,6);②抛物线的对称轴是在y轴的右侧;③抛物线一定经过点(3,0);④在对称轴左侧,y随x增大而减小.从表可知,下列说法正确的个数有( )
A.1个
B.2个
C.3个
D.4个
0 137360 137368 137374 137378 137384 137386 137390 137396 137398 137404 137410 137414 137416 137420 137426 137428 137434 137438 137440 137444 137446 137450 137452 137454 137455 137456 137458 137459 137460 137462 137464 137468 137470 137474 137476 137480 137486 137488 137494 137498 137500 137504 137510 137516 137518 137524 137528 137530 137536 137540 137546 137554 366461
| x | … | -3 | -2 | -1 | 1 | … | |
| y | … | -6 | 4 | 6 | 6 | … |
A.1个
B.2个
C.3个
D.4个