Stuck on a few Hydrogen Bonding questions

I was asked to choose which molecules form hydrogen bonding between molecules in a sample of the pure substance

a.)CH4
b.)NH3
c.)CH3-OH
d.)CH3-CH2-O-CH2-CH3

I chose B and C. Are there others?

Also

Out of the 4
I was told to select ONE molecule that does not form hydrogen bonding as a pure substance, but DOES form Hydrogen bond in a solution with one of the other compounds..

I'm kinda stuck on this..

B and C
B and D
C and D

NH3 is the one molecule that can be a hydrogen bond donor in acidic solutions since it will be protonated to NH4+, however in its protonated form, this NH4+ cannot be a hydrogen bond acceptor since it does not have a lone pair of electrons on the heterocylic atom (N)

all you need to form a hydrogen bond is a Hydrogen bonded to a heterocyclic atom (N, O, or S) to be the hydrogen bond donor, and a heterocyclic atom (N, O, or S) with a lone pair of electrons to be a hydrogen bond acceptor.

Hope this helps.