During the first half of the 1900's these kinds of laws were enforced in the
southern United States, but not in the Northern states.

I believe these kinds of laws were known as Jim Crow Laws which was a law of segregation mostly done in the southern states of the 1900s. The northern states weren't 100% non-jim crow but the majority of north didn't have those laws.

answer; i believe the correct answer is (proximity);

i this is the answer i looked it up on google so in 2020 new year's occurs on january 1st, 2020 and christmas on december 25th, 2020. these dates are 51 weeks and 2 days apart, not one week apart (during the year new year's occurs before christmas).