Fedora Technologies acquired 60 hard-drives and tried selling them at BDT 2400 apiece at 20 percent markup on cost price. After 3 months, 6 remained unsold and were returned to manufacturer at 50 percent refund of cost. Find out Fedora's approximate profit margin as a percentage of initial acquisition cost of the 60 hard-drives.

1. ক5%
2. খ7.5%
3. গ10%
4. ঘ12.5%