In paper 1 of iit jee 2010, there was one multiple answer question on thermodynamics(based on graph). Many institutes(like fiitjee,brilliant etc.) gave the answer for that question as (a) and (b), and the reason they gave for (c) and (d) ALSO not being the answers is that it is not clear whether line(segment) BC(pls see the question/graph) passes through the origin or not.Now when u luk at the graph, it DOES seem a like BC passes through the origin due to which options (c) and (d) would also be the answers.Such a speculation is also going on.I would like to ask what would be the correct answer and for such a question, is it to be assumed(by default) that BC doesnt pass through origin, and whether it would be mentioned in the question directly or indirectly in the question to indicate BC passes through the origin.

In paper 1 of iit jee 2010, there was one multiple answer question on thermodynamics(based on graph). Many institutes(like fiitjee,brilliant etc.) gave the answer for that question as (a) and (b), and the reason they gave for (c) and (d) ALSO not being the answers is that it is not clear whether line(segment) BC(pls see the question/graph) passes through the origin or not.Now when u luk at the graph, it DOES seem a like BC passes through the origin due to which options (c) and (d) would also be the answers.Such a speculation is also going on.I would like to ask what would be the correct answer and for such a question, is it to be assumed(by default) that BC doesnt pass through origin, and whether it would be mentioned in the question directly or indirectly in the question to indicate BC passes through the origin.