The correct option is (b) Angiotensin-converting enzyme inhibitor
The explanation: Second-line treatment which includes adding drugs such as Angiotensin Converting Enzyme (ACE) Inhibitor, Calcium Channel Blocker, Angiotensin II Receptor Blocker (ARB), α- blocker, α- and β-blocker. And line should be given when 1^st line treatment with lifestyle modification, initial drug selection should be diuretic, beta-blocker is in adequate. If 2^nd line treatment is inadequate, continue to third line treatment increase drug dose or Substitute another drug or add a second drug from another class. If inadequate may need to do further studies serious organ damage may be present.