Need advice on taking offer

I am a student working a BO internship at a large European bank and I have received an internship offer to start part-time unpaid immediately at an investment fund in my desired market.

This offer is 100% more attractive to me than the BO one but I have three major problems: 

1. Internship start and end dates will overlap; the investing internship is part-time and will ramp up next semester when my work finishes but there is still that tiny overlap where I am FT in BO role and PT in investing role

2. In previous roles I have applied to, I indicated that I will be working this BO role for x amount of time meaning if I convert any of those, I cannot quit 

3. This role is unpaid and PT while my current role is paid and FT; the experience is great but this plays a small factor 

Right now, it seems my options are 1) take role and work both 2) decline role and stay in BO 3) quit BO internship and work at fund (least inclined to do this because it is only PT + unpaid) 

My end goal is that I want to be in an investing role but the problems above are what is stopping me. What would you guys do?