6861. The pioneers left a blazing trial of courage, manliness and chivalry.

✅ The correct answer is option D.
inventors : a person who invented a particular process or device or who invents things as an occupation.

explorers : a person who explores a new or unfamiliar area.

colonialist : a person who supports the practice of gaining political control over other countries and occupying them with settlers.

settlers : a person who moves with a group of others to live in a new country or area.

pioneers : a person who is among the first to explore or settle a new country or area.

Synonym of pioneers is settlers