The correct answer to this open question is the following.
Although there are no options attached or further context, we can say the following.
If a sales promotion increases an organization's profits, it means it has fixed any problems with the marketing plan.
Not really, it only means that the sales promotion was effective up to the degree of the goals established in the plan. But this doesn't mean that it has solved all the problems with a marketing plan
The marketing plan is a more large and complete document that includes many different strategies, tactics, and action programs. The sales promotion is only one aspect or program of the marketing mix included in the plan.