Final answer:
The correctly punctuated statement that is not a comma splice is option a), which uses a coordinating conjunction to join two independent clauses. Options b), c), and d) are not correctly punctuated and contain comma splices.
Step-by-step explanation:
The one correctly punctuated statement that is not a comma splice is:
a) Steve Jobs cofounded Apple Computers with Steve Wozniak in 1976, but Jobs was phased out of the company during the 1980s after it experienced major setbacks.
This statement is correct because it uses the coordinating conjunction 'but' to join two independent clauses, avoiding a comma splice. The other options b), c), and d) all have incorrect punctuation leading to comma splices by attempting to use 'however' without a semicolon or by incorrectly trying to link independent clauses with a comma. To avoid a comma splice, one should use proper conjunctions, a semicolon, or a period to separate independent clauses.