当平面过锥顶截切圆锥，产生的截交线是。

A. org.gjt.mm.mysql.Driver
B. org.gjt.mm.mysql.Driver.Driver()
C. org.gjt.mm.mysql.Driver.class
D. org.gjt.mm.mysql

A. jdbc:mysql://127.0.0.1:3306/
B. mysql://localhost:3306/userdb
C. jdbc://localhost:3306/userdb
D. jdbc:mysql://127.0.0.1:3306/userdb

A. DriverManager.connection(url, user, password);
B. DriverManager.get(url, user, password);
C. DriverManager.getConnection(user, password);
DriverManager.getConnection(url, user, password);