Answer:
-3.7555 M/s is the rate of change of B.
Explanation:
3A + 5B → 4C
Given that rate of the reaction ,R= 0.7511 M/s
Rate of the reaction is defined as change in concentration of any one of the reactant or product with respect to time.



The negative sign indicates the concentration of reactant B is decreasing with progress in time. This mean reactant B is disappearing.
-3.7555 M/s is the rate of change of B.
I don't think it's any of the above. Because there is two double carbon bonds and it belongs to an alkene, it should be an ethene molecule.
3 elements are in one chemical