To what extent should a question such as: "how many enantiomers are there?" take geometric isomerism into account?

Pretty simple question here.



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> How many enantiomers are there for the structure $\ce{CH3CH=CHCH(CH3)CH2CH3}$?
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On the one hand, there is just one chiral centre so one would suggest $2$. On the other hand, there is some E/Z cis/trans isomerism at play leading to four distinct *stereo*isomers.


I made a sketch:


[![Displayed formulae of stereoisomers](https://i.stack.imgur.com/rXdID.png)](https://i.stack.imgur.com/rXdID.png)


If I'm not mistaken, $(A)-(D)$ are distinct molecules. Let's say we favour $(A)$. Would we say that the only enantiomer of $(A)$ is $(B)$, or would we say that all of $(B),(C),(D)$ are enantiomers of $(A)$?


I ask because I have been hearing some confused messages from my chemistry teacher and for a question as specific as this, I could not find a satisfactory online discussion. I would personally count them all as different enantiomers since it is truly a different arrangement of atoms in space and it is reasonable to suppose that all of them have slightly different optical properties.


What would you say?


