Maya, not the residency, is the topic. The committee offered Maya a six-month residency, so the focused passive is: Maya ___.
was offered a six-month residency✓Respuesta correcta
offered by the committee a six-month residency
was offering the committee a six-month residency
was offer a six-month residency by the committee
Explicación
Was offered a six-month residency makes the person the passive subject and therefore preserves the stated focus. A thing-subject version with to is also standard, but it would foreground the residency instead.