Attention Weight with Relative Positional Encoding

A language model is designed to generate a sentence one word at a time, from beginning to end. To generate the word at a specific position i, it uses an attention mechanism to weigh the importance of the words that came before it. Which of the following statements correctly analyzes the structural constraint required for this mechanism to function properly for this specific task?

Formula for Attention Weight with Relative Positional Encoding

Analyzing Attention Mechanism Constraints

An autoregressive model is processing the input sequence 'The quick brown fox'. When calculating the output representation for the token 'brown' (the third token), which set of tokens can it attend to if a causal attention mechanism is being used?