Comprehensive and Detailed in Depth Explanation:

Enabling a secrets engine in Vault follows a specific syntax:

A: Incorrect syntax; jumbled order.

B: Correct: vault secrets enable < type > enables the AWS engine at aws/. Correct.

C: Incorrect word order.

D: Incorrect syntax.

Overall Explanation from Vault Docs:

“The command vault secrets enable < type > enables a secrets engine at its default path (e.g., aws/ for AWS).”