The only answer that makes sense is "C". Crawling from shell hole to shell hole is slow, and still dangerous, but the other choices can get you killed quickly. The Germans will let loose with their machine guns, rifles ,mortars and artillery as soon as they see an attack forming. Anyone standing up is a target.

I know you were taught at camp to attack in waves with bayonets, but this doesn't work against machine guns. But if your officers order it, you do it, and you die.

Attacking while carrying a machine gun simply isn't possible. They weigh over 60kg, plus another 60 for the ammunition. No one could make more than a few steps loaded like that.

Using horses sounds good, but it was tried and failed. No Mans Land is too rough, with too much mud for horses, and anyone riding on top of a horse is an easy target.