A sales clerk at Big C Store observed a customer remove a watch from a display case and put it in his pocket. In most cases, Big C: 

a. can detain the customer for suspicion of shoplifting. 
b. cannot detain the customer but can alert the police. 
c. cannot detain the customer but once the customer leaves the store, the sales clerk can make a citizen's arrest. 
d. cannot detain the customer but can sue for conversion.