The answer is 2.
While you're in this section of the forum, you might want to check out the
Early Access FAQ.
In particular
I already own Baldur’s Gate for PC on Early Access, do I have to buy another copy for the Digital Deluxe Edition content?
You don’t have to! If you own Baldur’s Gate 3 on PC/Mac or are planning to purchase it on Early Access before launch, you will get a free upgrade to the Digital Deluxe Edition! Since This edition includes 72h of early access, this means you will get access to the Digital Deluxe Edition content on August 28th!
The same goes for owners of our Collector’s Edition.
[...]
How does the 72h early access to Act 1 work?
All owners of the Digital Deluxe Edition of Baldur’s Gate 3 will be able to access the game 72h before launch day, on August 28th.
This early access will contain the final launch version of Act 1 and the saves will carry on and be compatible with the full game on August 31st.
In addition, remember
Will Early Access saves be compatible with the full release?
No. Due to the amount of updates and changes expected during the Early Access stage and at launch, saves made during Early Access will not be compatible with the full version of the game when it releases.
If by "clear" you mean that you'll have to start over, yes, you'll have to start over. I don't think the saves will be erased from your hard drive. They'll just become incompatible and unusable. Possibly, you will be able to see them in the game (and, e.g., remember the names of your EA characters), but they won't load.
