Should I add the acronym in my URL

[igotBAWS]

Hello SEO-Masters!

How should I structure my URL for acronyms (abbreviations)?

Currently, it's like this:
Basic Guide on theme: https://www.coinstaker.com/initial-coin-offering
Basic Review of someone in this theme: https://www.coinstaker.com/initial-coin-offering/company-1

Abbreviation of initial-coin-offering is ICO. The SEO fight for the "ICO" keyword I have currently lost.

This is, of course, to be changed. I see four possibilities:

1. https://www.coinstaker.com/ico.
Cons: Duplicate content handling would be tedious and not user-friendly

2. https://www.coinstaker.com/initial-coin-offering/ico

3. https://www.coinstaker.com/initial-coin-offering-ico

4. https://www.coinstaker.com/initial-coin-offering/company-1-ico


Really not sure which SEO perspective is the best.

Thanks in advance for your help!