Topic: Linkers or Connectors,

Best Answer Explained in Below-:

The phrase "No sooner had he got notice --- he changed his direction" requires a word that indicates a swift sequence of actions. In English, "no sooner... than" is a common correlative construction used to express that one event quickly follows another. This structure emphasizes the immediacy of the second action in relation to the first.

Using "than" is important here because it indicates that as soon as the first event occurred (receiving notice), the second event (changing direction) happened right after, creating a clear cause-and-effect relationship.

In contrast, the other options—"as," "before," and "after"—fail to appropriately convey this immediacy. "As" would imply simultaneous actions rather than one following the other, while "before" and "after" suggest a more extended time gap between the actions. Therefore, "than" is the correct choice as it accurately captures the rapid succession of the two events, making it the most fitting word for this specific context.