Available Akismet options in Contact Form 7

Can anyone advise what are all the akismet option available for contact form 7?

I am trying to get Akismet to validate message content (see my code example below under “Your Message”) of my contact form by using akismet:content but it did not work. I “guessed” this option based on what I can find at https://akismet.com/development/api/ but it didn’t work.

<p>Your Name (required)<br />
    [text* your-name akismet:author] </p>

<p>Your Email (required)<br />
    [email* your-email akismet:author_email] </p>

<p>Your Message (required)<br />
    [textarea* your-message akismet:content] </p>

Can someone advise?

Thanks in advance.

https://www.ads-software.com/extend/plugins/contact-form-7/
https://www.ads-software.com/extend/plugins/akismet/