Which costs are explicitly paid by the issuer?

The correct choice highlights the specific costs that an issuer directly incurs in the process of issuing debt instruments such as bonds. Costs associated with management advisory services, legal counsel, bond trustee fees, and auditor costs are essential components of the bond issuance process. These expenses arise directly from the actions necessary to issue the debt, including ensuring legal compliance, management of the bonds, and maintaining the necessary financial standards.

These costs are considered explicit because they must be budgeted and accounted for in the financial planning of the issuer. They are predictable, contractual expenses agreed upon by various professionals who assist in the issuance of debt. This contrasts with other options which either include costs not directly associated with issuing debt or are more operational in nature rather than directly incurred for debt issuance. For instance, costs like investment banking fees could be argued to fit in another context, while operational costs or marketing fees are not directly related to the debt issuance process, reducing their relevance to the question posed.