Serms aromatase inhibitors

In the context of adjuvant therapy for hormone receptor-positive breast cancer, which of the following statements is accurate regarding the use of aromatase inhibitors (AIs) and selective estrogen receptor modulators (SERMs)?

1: SERMs are generally used for a shorter duration than AIs.
2: Patients may switch from a SERM to an AI to complete adjuvant therapy.
3: AIs and SERMs are typically used concurrently.
4: SERMs are typically used as a follow-up treatment after completion of AI therapy.