A vendor sells hotdogs at $15 /piece. For every hot dog he spends $12 in the raw material. Additionally, he spends $1 for packing each hotdog and monthly $50, $20, $10 as food truck rent, electricity and other expenses respectively. How much is the vendor contributing to covering his fixed costs or generating profits (contribution margin)? 1) 5 2) 6 3) 3 4) 2