Should I choose visa classification as B2 or B1/B2

I have submitted the DS-160 for my parents with the classification as B2 and paid the visa fee but still yet to schedule the appointment. Few of my friends told me to change the visa classification from B2 to B1/B2, is it ok to go ahead with B2 or do I need to change it? I explored the internet but I’m confused with both kind of answers. Please help me to decide, appreciate your help and support.

Unless your parents intend to visit the US for business purpose, they should apply for B2.