Answer:
The statement that is best written is the second one. It's just missing the capital letter at the beginning, but it has sense "Por fin, él arregló la computadora".
Other sentences are just wrong, for example, the first one would be "recibi un aumento este mes", the word "de" is not necessary. Others are incomplete, for example, "mi madre es de español en la escuela secundaria" or "tuve una entrevista con la de esta oficina", these don't make senes.
It would be better like this:
"Mi madre es la maestre de español en la escuela secundaria"
"Tuve una entrevista con la jefa de esta oficina"
Therefore, I pick the second statement, because it has minor errors.