What is the most appropriate next step in management?

A 26-year-old man presented urgently, complaining of muscle pains. He had been found to have heterozygous familial hypercholesterolaemia 2 years previously owing to a mutation in the PCSK9 gene. He had a strong family history of premature vascular disease. He was taking atorvastatin 80 mg daily.

Investigations:

serum creatine kinase2782 U/L (24C195)

serum cholesterol5.7 mmol/L (<5.2)

After stopping atorvastatin, his serum creatine kinase fell to within the normal range.

What is the most appropriate next step in management?
A . restart atorvastatin 10 mg
B . restart atorvastatin 40 mg
C . start ezetimibe 10 mg
D . start fenofibrate 100 mg
E . start fluvastatin 40 mg