Ihave never met someone who does his job so well; he is consistently professional. use a semicolon to join closely related independent clauses. use a colon to separate items in a series. use a semicolon to join closely related dependent clauses.

The answer is "use a semicolon to join closely related independent clauses".

The semicolon or semi colon refers to a punctuation mark that isolates significant sentence components. A semicolon can be utilized between two firmly related independent clauses, if they are not effectively joined by a planning or coordinating conjunction.