“The TV is too noisy，Mum．”“Sorry，my dear．I'll ______ at once．”

　　A．turn it down　　B．turn it on　　C．turn it up

---The TV is too noisy，Mum．

---Sorry, dear．I’ll __________at once．

A．turn it down            B．turn it on            C．turn it up         D．turn down it