My recommendation is:

Use

addTrack( ITrack t ) 

but be sure that ITrack is an interface and not a concrete class.

Album doesn't know the internals of ITrack implementors. It's only coupled to the contract defined by the ITrack.

I think this is the solution that generates the less ammount of coupling.

My recommendation is:

Use

addTrack( ITrack t ) 

but be sure that ITrack is an interface and not a concrete class.

Album doesn't know the internals of ITrack implementors. It's only coupled to the contract defined by the ITrack.

I think this is the solution that generates the least amount of coupling.