Which is the most effective way to combine sentences 1 and 2?

During World War II, many men were drafted yet many others volunteering to serve.

Many American men were drafted during World War II, or many other men volunteered to serve.

Many American men were drafted during World War II, and many other men volunteered to serve.

During World War II, many men were drafted, others volunteering to serve.

During World War II, many men were drafted, and many others volunteered to serve.