Which Coherence caching pattern matches the sequence of events ？（） 1. Data is requested from cache 2. The requested data does not exist in the cache （cache miss） 3. The Coherence cache store is used to red data from the back-end persistent data source， and placed in ther cache 4. Data requested from the cache is returned to the caller
- A read through
- B write through
- C refresh ahead
- D write behind