You are creating an App Engine application that uses Cloud Datastore as its persistence layer. You need to retrieve several root entities for which you have the identifiers. You want to minimize the overhead in operations performed by Cloud Datastore. What should you do?

A. Create the Key object for each Entity and run a batch get operation B. Create the Key object for each Entity and run multiple get operations, one operation for each entity C. Use the identifiers to create a query filter and run a batch query operation D. Use the identifiers to create a query filter and run multiple query operations, one operation for each entity