D.
There is definitely a curriculum but it's not like in traditional school. The lessons are given with the manipulatives. The guide will introduce lessons and as your child shows readiness, will take him to the next level of work. It is all at the child's pace and not dictated by the whole class. The philosophy is to meet the child where they are at and move forward from there. Parent education is a big part of Montessori. As you learn more about it you will begin to see the structure in what seems like chaos at first. Do some reading and see if you like it. I put my first child through Montessori education from 2 yrs old to 15 yrs old and never regretted it. In fact I now work at the school and have started my 3 yr old and 2 yr old in the program.
Be wary of schools that claim to be Montessori though. Some only have a few of the materials but not trained teachers. Look for either an AMI or AMS certified school and teacher. A good school will always strive to follow the child.