Step 1: Extortionate credit transactions.
Sections 50 and 51 of the Insolvency and Bankruptcy Code, 2016 specifically deal with extortionate credit transactions in corporate and individual insolvency processes.
Step 2: Other related provisions.
Section 167 appears in the context of avoidance transactions in individual insolvency.
Step 3: Identification of unrelated provision.
Section 173 does not deal with extortionate credit transactions and relates to a different procedural aspect of insolvency law.
Step 4: Conclusion.
Therefore, the correct answer is (D) Section 173.