Funny that's how your (2019) MKC reads, this is from my 2017 manual:I'm going to go with 89 or 93. Probably 93 which is 50 cents more here in SC.
Page 165 manual in states..
"For best overall vehicle and engine
performance, premium fuel with an octane
rating of 91 or higher is recommended."
I like a vehicle that runs at its optimum performance level.
SourceWe recommend regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. Some stations offer fuels posted as regular with an octane rating below 87, particularly in high altitude areas. We do not recommend fuels with an octane rating below 87. To provide improved performance, we recommend premium fuel for severe duty usage such as trailer tow.