Answer: "The central character who has to overcome the main conflict in the story" ---> the protagonist
"The character who opposes the lead character and is the main source of conflict" --> the antagonist
"The character with ordinary qualities providing support to important characters" ---> the secondary character
Step-by-step explanation: There are several types of characters in a story. The most important one is the protagonist since he/she is at the center of the story. In other words, the protagonist is the character that makes the decisions, faces the consequences and experiences a conflict. The enemy of the protagonist is the antagonist, who is generally identified as "the villain" since he/she has bad intentions and his/her values and beliefs oppose to the ones of the main character. A secondary character, on the other hand, usually helps the protagonist, reveals an important secret or allows the reader to identify the setting of the story. In that way, a secondary character does not have a key role in the development of the storyline.