A. There are no clues to distinguish it from a regular article.
Explanation:
Native Advertising is when the ad blends perfectly with the platform it is displayed upon and does not look like an advertisement at all.
For example: on an article website, the advertisement will be masked as an article that fits in with the niche of the website so it does not feel out of place and legitimately promotes what it tries to promote.
These ads must fit editorial standards of the publication as well as audience's expectations.