Which one of the sentence sequences in the given options creates a coherent narrative?

(i) I could not bring myself to knock.
(ii) There was a murmur of unfamiliar voices coming from the big drawing room and the door was firmly shut.
(iii) The passage was dark for a bit, but then it suddenly opened into a bright kitchen.
(iv) I decided I would rather wander down the passage.

The correct option is (ii), (i), (iv), (iii).

To establish a coherent narrative, we need to trace the logical flow of actions and spatial transitions of the narrator:
1. Sentence (ii) ("There was a murmur of unfamiliar voices coming from the big drawing room and the door was firmly shut.") sets the initial scene. The narrator arrives at a closed door and hears voices from inside.
2. Sentence (i) ("I could not bring myself to knock.") directly follows from the context of the shut door and unfamiliar voices. Because of the hesitation caused by the unfamiliar voices behind the closed door, the narrator decides not to knock.
3. Sentence (iv) ("I decided I would rather wander down the passage.") explains the alternative action the narrator takes instead of knocking. This transitions the narrator away from the drawing room door.
4. Sentence (iii) ("The passage was dark for a bit, but then it suddenly opened into a bright kitchen.") describes the experience of wandering down the passage mentioned in sentence (iv) and provides the conclusion of this spatial journey.

Therefore, the sequence that constructs a clear and logical narrative flow is (ii), (i), (iv), (iii).