Yup, sure is the longest running theological debate. Anyway, I chose option 2 and 3, as those are closest to what I believe.
I will say, though, that although one cannot say imo that one can lose faith and still be saved, one can believe, and hope, that God's Grace will keep you from failing in the faith until the end. This is the Augustinian idea of Perseverance in the Faith being a distinct Grace from Initial Justification. After Justification, we must pray for Perseverance. If/when we receive it (and we surely will receive it, if we persist in asking for it, since God has promised to give us the good things we ask for, according to His will and wills all of us to be saved and not perish), after that, His Grace will keep us from ever denying faith.
In the Calvinist idea of TULIP, the P in TULIP stands for "Perseverance of the Saints". St. Augustine also wrote about Perseverance, and Calvin said his idea of Perseverance was based on what Augustine wrote, but the two are slightly different. Here is an excerpt from that work.
"Chapter 9.— When Perseverance is Granted to a Person, He Cannot But Persevere.
Now, moreover, when the
saints say, Lead us not into
temptation, but deliver us from
evil,
Matthew 6:13 what do they
pray for but that they may persevere in
holiness? For, assuredly, when that gift of God is granted to them — which is sufficiently plainly shown to be God's gift, since it is asked of Him — that gift of
God, then, being granted to them that they may not be led into
temptation, none of the
saints fails to keep his perseverance in
holiness even to the end. For there is not any one who ceases to persevere in the
Christian purpose unless he is first of all led into
temptation. If, therefore, it be granted to him according to his
prayer that he may not be led, certainly by the gift of God he persists in that sanctification which by the gift of God he has received."
https://www.newadvent.org/fathers/15122.htm
So, in other words, after you receive the Grace of Perseverance (distinct from the Grace of Justification), and you receive this Grace, for e.g. by saying Our Lord's Prayer, the Our Father, often, and specifically asking for this Grace, after that, you will never fall from your Faith in Christ, and thus persist in the sanctification you have received, and so be saved.
That's the traditional/Augustinian view of the Church Fathers, which could perhaps be called "OPAS" (Once Perseverance is given, Always Saved), and several Biblical passages imo accord with this Truth. Will cite those later on.
God Bless.