Who are the most important senate officers, and what are their jobs?

The President of the Senate. The president is the main leader of the Senate. The president presides over the daily Senate sessions, preserves order, appoints committee chairs and members, refer bills to committee, signs legislation, writs and warrants, and act as the official spokesman for the Senate.  

President pro tem of the Senate. The primary roles assigned to the president pro tem are to preside over the Senate in the president's absence and exercise the powers and duties of the president in his or her absence.

Speaker of the House. The speaker is the principal leader of the House. The speaker presides over the daily sessions of the House, preserves order in the chamber, states parliamentary motions and rules on parliamentary questions. They appoint committee chairs and members, refer bills to the committee, sign legislation, writs, and warrants and act as the official spokesman for the House.

Speaker pro tem. The primary roles assigned to the speaker pro tem are to preside over the House in the speaker's absence, exercise the powers and duties of the speaker in his or her absence and assume other duties as assigned by the speaker.  

Majority Leader. The primary functions of a majority leader usually relate to floor duties. The majority leader is the lead speaker for the majority party ( depends on which party is the majority at any given time) during floor debates, develops the calendar, and assists the president or speaker with program development, policy formation, policy decisions.

Majority Caucus Chair. The majority caucus chair develops the majority caucus agenda with the principal leaders and presides over the majority caucus meetings.

Majority Whip. The majority whips' main duties are to assist the floor leader,  ensure member attendance, count votes, and communicate the majority position.

Minority Leader. The minority leader is the main leader of the minority caucus. The minority leader is responsible for developing the minority position ( where they stand on bills coming up for a vote), negotiating with the majority party,  directing minority caucus activities on the chamber floor, and leading debate for the minority.

Minority Caucus Chair. The minority caucus chair presides over caucus meetings and assists the minority leader with policy development.

Minority Whip. The major responsibility of the minority whip is to assist the minority leader on the floor, count votes, and ensure the attendance of minority party members.

Explanation:

b or c ( this is because my answer is short so just ignore it)

c, to compete