challenge: What is an F-cover of a module M in algebra?
  
  A. A homomorphism X→M with certain properties related to a family of modules F over a ring R
  B. A homomorphism X→M with the properties of being injective and surjective
  C. A homomorphism M→X with a specific set of properties
  D. A homomorphism X→Y with no specific properties
  Answer: 