连接BE,
∵AE是直径
∴∠ABE=∠ADC=90°
∵∠E=∠C
∴△ABE ∽ △ADC
∴
AB
AD =
AE
AC
∵AB=4,AC=3,AD=2,
4
2 =
3
解得:AE=6,
故选B.