What are the main causes of secondary hypertension?

Hypokalemia, hypomagnesemia, and hyperthyroidism are some of the underlying exacerbating disorders.
Digoxin and drugs that prolong the QT interval are exacerbating medications.
Ethanol, cocaine, and other stimulants are some of the toxins that can cause secondary hypertension.
a) Only I is correct.
b) II and III are correct.
c) I, II, and III are correct.