The correct choice for Blank (i) is C. disbelief.

Detailed Analysis
1. Analyze the Contrast and Problem: The sentence describes a production (a multi-era saga) where the same character is played by two different actors.
- Problem: The actors are "distinguishable enough" that the audience "is able to discern differences for which the mere passing of years cannot account."
2. Determine the Required Meaning: The audience sees differences that are not explained by aging (e.g., Actor A has a different demeanor or physical feature than Actor B). This break in continuity challenges the audience's willingness to accept the illusion that they are watching the same person.
3. Evaluate the Options:
- A. surprise: Too weak. Surprise is a brief feeling, not an ongoing element interwoven into the saga.
- B. foreboding: A sense of future doom. (Irrelevant.)
- C. disbelief: The inability or refusal to accept that something is true. This perfectly captures the audience's mental struggle when the visual evidence (the actors) contradicts the narrative reality (it's supposed to be the same character). The audience has to suspend their disbelief because the evidence is weak.
- D. confusion: While the audience might be momentarily confused, the core issue is the acceptance of the character change, which is best described as an element of disbelief the audience must overcome.
- E. predictability: The opposite of the effect described.

The completed sentence reads:
An element of disbelief on the part of the audience is interwoven into the multi-era saga, for two actors portraying the same character at different phases of life are distinguishable enough that the audience is able to discern differences for which the mere passing of years cannot account.