The correct answer is B. Checking the scaling configurations is the most appropriate first step because it directly relates to the issue of the application not scaling up in response to increased demand. Issues with scaling configurations, such as incorrect thresholds or metrics set, can prevent auto-scaling features from operating correctly. Other options, like reviewing SLAs and bandwidth usage, may be part of a broader investigation but do not directly address the most probable cause of the issue, which is related to scaling configurations. An analysis of SLAs might be informative but would not yield immediate solutions to scaling problems. Allocating more static resources could circumvent scaling configurations but would not address the underlying issue with the scaling policies.