Answer: Wipe it completely clean.
Explanation: The only true way to wipe out a possible virus is to wipe a computer completely clean. When you wipe the computer clean, you are starting from scratch and have a better chance of not receiving another virus moving forward.
Sorry I don't know what is wrong with your headphones. Maybe try plugging them into something else.
Answer:
D. Block
Explanation:
Semantic HTML or semantic markup is HTML that introduces meaning to the web page rather than just presentation. For example, a <p> tag indicates that the enclosed text is a paragraph. This is both semantic and presentational because people know what paragraphs are, and browsers know how to display them.
Answer:
Number.
Letter is for columns, Number is for rows.
For example to find the cell on the fifth row, and 1st column, it would be A5.