a. Oral Sex - this still causes transfer of sexual fluids which can spread HIV. Technically if sexual fluids come in contact with toilet seats or clothing (underwear, etc), than HIV can be spread through those. But the chances of contracting HIV must be slim for those options since the fluids need to find a cut or an open blood vessel to enter.
The appropriate answer would be C. It could lead to other health issues.
The correct sentence is option two:
There have been many accidents during airshows; for example, last year the wind toppled a tent and equipment on top of bystanders.
The semicolon is a punctuation mark which indicates a pause, usually between two clauses that are not joined by a coordinating conjunction. Semicolons can also replace commas to separate elements in a list that already includes commas.
In the example sentence, the semicolon separates two clauses. Besides, a comma follows the introductory phrase "for example" because it introduces a clause.
