"This generation?"

Jesus said, in Mark 13:31 while talking about the end times,

"I tell you the truth, this generation will certainly not pass away until all these things have happened. Heaven and earth will pass away, but my words will never pass away."

What did Jesus mean by "this generation"? I think there are basically three possibilities: literal, figuaritive, and combination.

Literal: Jesus literally meant that the generation of his listeners would actually see the events described in Mark 13 and that Jesus would return to collect the collect within about 40 years of his resurrection.

Figurative: "this generation" refers not to the literal generation of Jesus' hearers, but to the generations of Jesus' followers that will experience the gathering of the elect over the course of history until Jesus' progressive return is complete.

Combination: Jesus' words are both literal and figurative in the sense that Jesus' followers do experience the trauma described in Mark 13, but they don't experience the full return of Christ. They experience a portion of the "gathering" as the Holy Spirit begins to build the church in the first century. "This generation" also figuratively applies to Christians of all ages who are experience tribulation and wars and earthquakes, the elect who are being gathered as the Son of Man comes slowly towards earth with "great power and glory."

My conclusions:
* "this generation" is both literal and figurative
* the coming of the Son of Man is progressive
* the gathering of the elect represents the growth of the church (not the rapture)
* the tribulations described in Mark 13 are characteristic of all history leading up to the arrival of the Son of Man
* the climactic moment of return could be at any moment now