<prompt> Great cardiac vein drains into -Anterior cardiac veinCoronary sinusThebesian veinVenae cordis minimi  <response>: Ans. is b i.e., Coronary sinus Veinous drainage of heart1. Coronary sinus: Opens into right atrium and has following tributries : i Great cardiac vein, ii Middle cardiac vein, iii Posterior vein of left ventricule, iv Small cardiac vein, v Oblique vein of left atrium and vi Sometimes right marginal vein.2. Anterior cardiac vein : Opens into right atrium.3. Venae cardis minimi thebasian veins : Open into right atrium.4. Right marginal vein : More often opens into right atrium but sometimes into coronary sinus. 