Final answer:
The 'I knew it all along' phenomenon is called hindsight bias, which is the belief that an event was predictable after it has happened. So, the correct answer is option a.
Step-by-step explanation:
The phenomenon of believing after an event has occurred that one "knew it all along" is referred to as hindsight bias. This type of bias makes us think that the outcome of an event was predictable, even when it wasn't. The hindsight bias is different from confirmation bias, which is the tendency to search for and interpret information in a way that confirms our preexisting beliefs and notions.
For example, if someone believes a professor is unfriendly, they might only notice behavior that supports this belief, despite other evidence that contradicts it. Similarly, availability bias involves making decisions based on the most immediate examples that come to mind rather than all possible outcomes.
Specifically, the answer to the question about the 'I knew it all along' phenomenon is hindsight bias, which is often confused with other types of cognitive biases such as confirmation bias or availability heuristic, but refers uniquely to the post-event perception of predictability.
So, the correct answer is option a.