Why there is no comment option below any answers? Is that a new update? How to comment now?

You have to go to another site to comment

The most obvious reason must be that they don't want it to turn into an absolutely uncontrollable cesspit in the run-up to the US elections.

Apparently they've done this before on similar occasions.Same idea as those countries that ban the sale of alcohol for the two days before a major election.

"Our goal is to create a safe and engaging place for users to connect over interests and passions. In order to improve our community experience, we are temporarily suspending article commenting. In the meantime, we welcome your feedback to help us enhance the experience."

there's your answer. 

It's been removed because people used it to troll other users. I guarantee you the next thing to go will be the anonymous feature.

Yahoo has Temporary Disabled Comments Until they turn them Back on you wont be able to Comment

on any Answers

They made a Announcement about it here is what they have to say about It

In order to strengthen and improve community and engagement with our audience, we are temporarily disabling comments. Our goal is always to create a safe, engaging place to connect over interests and passions. Please feedback to yahoocommentfeedback@verizonmedia.com

Commenting has been removed EVERYWHERE in Yahoo.  Answers, News, Sports, Style....

Look for the survey question to give them feedback on no comments.

Why can't anyone just read any of the answers on the hundreds of times this same question has been asked?

It's been removed. 

One more time: It's been removed, as you would've known had you scrolled through this subcategory just a short way and seen the DOZENS of posts about it, since it occurred last week. See below for Yahoo's explanation (it's also posted as a banner on the main YA page)

YA say they have temporarily disabled comments, but YA are still celebrating Christmas. 

Commenting on answers has been removed. For how long we don't know. It could be temporary, or it could be permanent.