Should marketing report to Business Development, Sales, HR, Accounting, or the C-suite?
The simple and hard answer is "it depends". It depends on what the longterm strategy and vision is for the company.
However, if you have the marketing function of your business reporting up through and being managed by another department then they are essentially that department.
Here's what happens when the marketing function reports through and is managed by another department:
In the AEC industry, most "Marketing Coordinators" need a title change to "Proposal Coordinators" because they are project pursuit specialists and should be in the Business Development department.
If you want to market your AEC firm, lead the industry (as well as your customers) in thought leadership, and focus on sustainable growth, then you may need to reconsider where your marketing team is reporting.