B1 Stay more than 3 months need solid reason for it

Hi Expert,

I am going for L1 interview, I just applied for L1 after my B1 travel complete.

I had stay in US for 3 months. Blogs shows me in L1 they can ask me why you had stay for B1 3 months.

I want a solid justification to prove my travel on B1 on 3 month stay.