Microorganisms Use Hydrogen Bonds to Attach Themselves to the Surfaces

Microorganisms use hydrogen bonds to attach themselves to the surfaces that they live upon. Many of them lose hold of the surface because of the weak nature of these bonds and end up dying or being washed away. Why don't microbes just use covalent bonds instead?

A) Covalent bonds are always permanent bonds-the microbes could never get OFF their surface if they used them.
B) Covalent bonds depend on completely giving up or completely accepting an electron to form the bond. This isn't possible for many microbes without dramatically altering their basic molecular composition.
C) Covalent bonds typically require enzymes to form/break, whereas hydrogen bonds don't. If covalent bonds were used, it would require much more energy and molecules to be contributed from the cell. Hydrogen bonds don't have these requirements.
D) Covalent bonds may have more specific and stringent requirements for what atoms can bond with what. This makes for stronger bonds, but also decreases the overall potential for bonds that could readily be created between the microbe and its desired surface.
E) C and D