A client with hypothyroidism was prescribed levothyroxine (Synthroid), a T4 replacement. The client was reading about hypothyroidism and asked the nurse why they are receiving only T4 replacement when hypothyroidism causes low T3 and T4 levels. What is the best response by the nurse?

T4 replacement does not require any TSH monitoring as is required with T3

Your body effectively converts T4 into T3 so replacing T3 is unnecessary

T3 and T4 cannot be administered together because they will become inactive

Drug therapy does not replace T3 because it is the inactive precursor to T4