连接BD、CD,由圆周角定理可知∠B=∠ADC,∠C=∠ADB,
∴△ABE∽△CDE,△ACE∽△BDE,
∴
=AB CD
=BE DE
,AE CE
=AC BD
=CE DE
,AE BE
由AD为直径可知∠DBA=∠DCA=90°,
∵DE=2,OE=3,
∴AO=OD=OE+ED=5,AE=8,
tanC?tanB=tan∠ADB?tan∠ADC=
?AB BD
=AC CD
?BE DE
=CE DE
?AB CD
=AC BD
?AE CE
=CE DE
=AE DE
=4.8 2
故选C.