Refer to the exhibit. HSRP has been configured and Link A is the primary route to router R4.  When Link A fails， router R2 （Link B） becomes the active router.  Which router will assume the  active role when Link A becomes operational again？" （）

• A、 The primary router R1 will reassume the active role when it comes back online.
• B、 The standby router R2 will remain active and will forward the active role to router R1 only in the  event of its own failure.
• C、 The standby router R2 will remain active and will forward the active role to router R1 only in the  event of Link B failure.
• D、 The third member of the HSRP group， router R3， will take over the active role only in event of  router R2 failure.