A. Schema.DescribeSObjectResult: This method is used to retrieve metadata about an SObject type (e.g., Account, Contact) in Apex, such as fields, record type info, and relationships between objects. It's crucial for understanding the structure and permissions of an object. When you're working in a Without Sharing context, which ignores the organization's sharing rules, you still may need to respect field-level security and CRUD (Create, Read, Update, Delete) permissions. By using Schema.DescribeSObjectResult, you can programmatically check whether the current user has the permissions to create records or access specific SObjects, helping enforce security at a granular level despite the broader Without Sharing setting.

D. Schema.DescribeFieldResult: This method provides metadata about a field on an SObject, including whether the user has create, read, update, and delete permissions on that field. This is essential for enforcing field-level security in a Visualforce page or Apex class that operates Without Sharing. Since Without Sharing bypasses the sharing rules, using Schema.DescribeFieldResult allows the developer to manually check and enforce field-level permissions, ensuring that users can only interact with fields they are authorized to access....