A consultant sot up and successfully tested anintegration between the source system and a sandbox environment of Salesforce When the integration was switched to the production environment of Salesforce, the consultant encountered API call limit errors.
What is the likely explanation for this?

A. Testing of the integration in the sandbox environment was insufficient.

B. The incorrect sandbox environment was used for testing.

C. The triggers associated with NPSP were disabled in the sandbox environment.

D. The API call limits were different for sandbox and production environments.