You have Cloud Functions written in Node.js that pull messages from Cloud Pub/Sub and send the data to BigQuery. You observe that the message processing rate on the Pub/Sub topic is orders of magnitude higher than anticipated, but there is no error logged in Cloud Logging. What are the two most likely causes of this problem? (Choose two.)

A. Publisher throughput quota is too small. B. Total outstanding messages exceed the 10-MB maximum. C. Error handling in the subscriber code is not handling run-time errors properly. D. The subscriber code cannot keep up with the messages. E. The subscriber code does not acknowledge the messages that it pulls.