Problem with sentence 1: You do not need a semi colon before "because" - only a comma.
Problem with sentence 2: You do not need a semi colon before "but" - only a comma.
Problem with sentence 3: You do not need a semi colon before "although" - only a comma.
Problem with sentence 4: Nothing.
Sentence 4 is correct.
sentence 4 has nothing wrong with it ;
The correctly punctuated sentence is option D: "I need to leave for school right now; however, I don't have all of my school supplies gathered." Options A, B, and C misuse semicolons before subordinating or coordinating conjunctions. Therefore, option D is the appropriate choice.
;