Both Josiah and Zephaniah were:

a) of royal lineage

b) descendants of Hezekiah

c) fourth-generation descendants of the same king

d) all of the above

Both Josiah and Zephaniah are descendants of Hezekiah, both are born of royal lineage and they are also fourth-generation descendants Hezekiah (all of the above). Zephaniah is the son of Cushi, and the great-great grandson of King. Josiah, on the other hand, was a seventh-century BCE king of Judah