What is the likely cause of this issue?

Universal Containers (UC) has created a custom Invoice object. Standard sales users at UC can see the records in search layout, but when they click to view the detail, only record name, created date, and last modified date are shown. When the system admin accesses it, he or she sees the full record detail with many more data fields.

What is the likely cause of this issue?
A . Sales users profile does not have access to the remaining fields.
B. Page layout assigned to sales user profile has only read-only access to the fields.
C. Org-wide sharing settings have been set to Private and need to be adjusted to Public Read/Write.
D. A role-based sharing is missing and should be added for the sales user’s role to grant access to the fields.

Answer: A