Tuesday.
It was a Wednesday
December 12 can fall on any day of the week.
December 9th, 1977 was on a Friday.
December 15, 1977 was a Thursday.
December 3, 1977 was a Saturday.
1 December 1977 was a Thursday.
27 December 1977 was a Tuesday.
December 5, 1977 was a Monday.
December 29 1977 was a Thursday.
December 1, 1977 fell on a Thursday.
December 8, 1977 fell on a Thursday.
December 30, 1977 fell on a Friday.