Final answer:
The pair of transformations equivalent to the given transformation is a reflection across the x-axis followed by a translation of 1 unit up.
Step-by-step explanation:
The transformation described by (x, y) -> (x, -y + 1) can be obtained by performing a reflection across the x-axis followed by a translation of 1 unit up. This means that option a) A reflection across the x-axis followed by a translation of 1 unit up is equivalent to the given transformation.