Describe the relationship between lvalue and rvalue.
An lvalue may appear on the left-hand or right-hand side of an assignment; an rvalue may appear only on the right-hand side.
An lvalue and an rvalue may appear on either left-hand or right-hand side of an assignment.
An lvalue may appear only on the left-hand side of an assignment; an rvalue may appear on either the left-hand or right-hand side.
An lvalue may appear only on the left-hand side of an assignment; an rvalue may appear only on the right-hand side.