Which website citation is correctly formatted according to MLAstandards?

the last one

Explanation:

It isnt the third one bc the authors name has to be first, and it isnt the first one bc the date you visited the site has to be there.

the president was the speaker and it was a great part of history.

explanation:

video of the national aeronautic space administration's (nasa) coverage of president john f. kennedy’s address at rice university, houston, texas, concerning the nation's efforts in space exploration. in his speech the president discusses the necessity for the united states to become an international leader in space exploration and famously states, "we choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard."