Google looks down upon paid links for enhancing page rank. If a website sells links, what action/s does Google recommend to avoid being penalized?

Question:Google looks down upon paid links for enhancing page rank. If a website sells links, what action/s does Google recommend to avoid being penalized?

1.The text of the paid links should state the words “paid text link” for Google to identify it as a paid link

2.Only Paid text links to non profit websites should be accepted

3.Paid links should be disclosed through the “rel=nofollow” attribute in the hyperlink

4.Paid links should be disclosed through the “index=nofollow” attribute in the hyperlink

Answer:3