Your reputation and credibility will be immediately destroyed if your website contains?

A. mediocre content.

B. grammatical errors.

C. special offers.

D. requests for email addresses.

Your reputation and credibility will be immediately destroyed if your website contains grammatical errors.

Explanation:

Any website will seek for email address to send newsletters and updates so that the website will be frequently visited and there is great chance to increase the number of visitors. So Option D is invalid

Option A: The meaning of mediocre is "average". If the content is average, then there will be visitors but not regular, but does not destroy reputation much.

Option C: Websites can have special offers to attract users. This option is also invalid

Option B: Websites should not contain grammatical errors. This spoils the reputation and credibility of the user.