Should be A C
IsShareable does not exist
isAccessible is used to test object/field access not the record visibility

A. Use with Sharing keyword in Apex classes to assure record visibility will be followed.
Implementing the with Sharing keyword in Apex classes ensures that the class respects Salesforce's sharing and security model. This means that any data access performed by the class is subject to the same visibility and access restrictions that apply to the running user, aligning with the intended security posture.

B. Use isAccessible keyword in Apex classes to assure record visibility will be followed.
The isAccessible method, part of the Salesforce Schema DescribeSObjectResult class, allows developers to check at runtime if the current user has permission to access a specific field on an sObject. This method can be used to programmatically enforce field-level security in custom Apex logic, ensuring that users can only access the data they are permitted to see.

Should be A & C since the isAccessible method only checks if the user can read a object/field.

A & B