Giventhatascopedattributecartexistsonlyinauser’ssession，whichtwo，takenindependently，ensurethescopedattributecartnolongerexists？（）

A.${cart=null}
B.<c：removevar="cart"/>
C.<c：removevar="${cart}"/>
D.<c：removevar="cart"scope="session"/>
E.<c：removescope="session">cart</c：remove>
F.<c：removevar="${cart}"scope="session"/>
G.<c：removescope="session">${cart}</c：remove>

【参考答案】

D, E