CA involves core accounting work and looking into the activities of day-to-day business. CAs require logical and methodical approach in work and attention to details. They need to possess good reasoning ability, problem solving skills and lots of patience to handle work responsibilities.
MBA is more of managerial work i.e. study of market economics, creating investment strategies, raising capital, effective utilization of resources, people management and so on. MBAs require ability to make proper decisions and implement them for the better prospects of the company. MBAs need to possess great communication and convincing skills.
In short, if you are good in numbers then CA is the career choice.
And if you think you can manage people and get things done, then MBA is the best option.