Residents of the District of Columbial, our nation's capital, gained the right to vote in
presidential elections in the year when
the
Amendment was passed.

23rd Amendment, ratified on 3/29/1961

Explanation:

https://en.wikipedia.org/wiki/Twenty-third_Amendment_to_the_United_States_Constitution#:~:text=The%20Twenty%2Dthird%20Amendment%20was,and%20the%20House%20of%20Representatives.

explanation:

an oligopoly is a term used to clarify the structure of a particular market, industry, or organization. a market is considered oligopolistic or amazingly focused when it is shared between a few companies.