Answer:
run-on (but technically, it is a comma splice -- but that answer option is not provided)
Explanation:
There are two independent clauses here. Two independent clauses must never be connected with a comma -- unless you add a coordinating conjunction. Alternatively, you may use a period with a capital letter, or you may use a semi-colon with a lower-case letter.
examples:
Softball was once an Olympic <em><u>sport, and</u></em> it was a way to showcase the talent of athletes.
Softball was once an Olympic <em><u>sport. It</u></em> was a way to showcase the talent of athletes.
Softball was once an Olympic <em><u>sport; it</u></em> was a way to showcase the talent of athletes.
A true run-on sentence would be this:
Softball was once an Olympic sport it was a way to showcase the talent of athletes.
Note that there is NO punctuation between clauses.