Answer:
Two great ball dancers began their careers in St. Petersburg, they were Anna Pavlova and Vaslav Nijinsky.
Step-by-step explanation:
A comma splice happens when two independent clauses are joint by a comma. To some is considered as a punctuation error and there are three different ways to correct it. Add conjunction, replace the comma with a semicolon or, the one I should use here, make each clause a sentence on its own.
I hope this answer helps you.