There is quite a bit of disagreement by Christians on the meaning of Ephesians 4.9.

- It refers to the incarnation (NIV Bible, Abbott, Barclay, Kent, Millard Erickson, Robertson)
- Christ’s descent after death into hell (hades) (Tertullian; Irenaeus; Jerome, Bengel, Olshausen; Meyer, Alford, Ellicott, Barry, Greene, Vincent, Wuest)
- Christ’s humiliation (Phil. 2.7; Ps. 139.15).
- Christ's physical death (Craig Keener)

As far as 1 Peter 3.19, it is widely recognized as perhaps the most difficult to understand passage in the entire New Testament. No one is firm on what it means, and there are abundant interpretations.

So saying, we don't build a theology on such shaky ground. Generally it is thought that if Christ did go to Hades (if one accepts that interpretation), the "prisoners" he ascended with were the God-believers who had been unable to enter heaven until the completion of Christ's redemptive work. (This view doesn't account adequately for what the texts say, but no explanation does. These texts are obscure to us.) So your "A" and "B" choices don't include all of the possibilities.

Does it imply limbo or purgatory? No. Purgatory contradicts the clear teaching of Scripture that Christ's substitutionary atonement is sufficient for our sin (Heb. 7.25-27) and that we ourselves are incapable of paying for our sins (Rom. 5.6-8). If we say that Christ’s work on the cross is not always sufficient for a person’s sins, we make Christ a liar. In essence, purgatory denies that we need a Savior; it implies that various people need to suffer physically to satisfy God. Verses like 2 Cor. 6.2 & Mt. 12.32, and a story like Luke 16.19-31, shows there is no biblical basis for purgatory.

What do you think happened during "The Harrowing of Hell"?

The Harrowing of Hell is where Jesus went after He died and before he was raised, to preach to the dead. Obstenably the idea behind the line of the Apostles' Creed "He descended to the dead/hell." Supported by Eph 4:9 and 1 Pet 3:18-20

But if there is one judgment (standard Christian dogma), then either a) those souls Jesus ministered to were already eternally damned; or b) not yet judged; dead, but not in heaven.

If A, then what was the purpose of the Harrowing? If B, does that imply there was/is a state of limbo or purgatory ("Abraham's Bosom" as the parable of the Rich Man and Lazurus puts it) where the righteous go/went before heaven?

Or does the Harrowing refer to something else? Such as Jesus descending into death and the Earth (referring simply to his separation from divinity)?