How do you think the location of the Union slave states affected their decision not to secede?

Four Slave States Stay in the Union

Despite their acceptance of slavery, Delaware, Kentucky, Maryland, and Missouri did not join the Confederacy. Although divided in their loyalties, a combination of political maneuvering and Union military pressure kept these states from seceding.

Explanation:

I was just searching so I'm not sure if that's right ... just correct if it's wrong

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.