【C015420】在Spring和Hibernate集成时，假如已经在Spring中配置了DataSource，并且id为datasource，则对SessionFactory正确配置的选项是（ ）。

• A.<bean id="sessionFactory" 
  
     class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  
   <property name="dataSource" value="dataSource" />
  
   ......略
  
  </bean>

• B.<bean id="sessionFactory" 
  
     class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  
   <property name="dataSource">
  
    <ref bean="DataSource"/>
  
   </property>
  
   ......略
  
  </bean>

• C.<bean id="sessionFactory" 
  
     class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  
   <property name="dataSource">
  
    <ref bean="datasource"/>
  
   </property>
  
   ......略
  
  </bean>

• D.<bean id="sessionFactory" 
  
     class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  
   <property name="datasource" />
  
   ......略
  
  </bean>