What are the elements to consider when using observation as an evaluation technique?

Observation must be intentional, specific, and systematic.
It requires prior planning to collect information about the problem, evidence, skill, or ability of interest.
Its fundamental purpose must be to improve the quality of the teaching and learning process, and therefore of the educational system.
Observing implies looking at the reality in which we find ourselves, not to judge it, but to try to understand it as deeply as possible and draw positive conclusions.
a) Only statements 1 and 2 are correct.
b) Only statements 2, 3, and 4 are correct.
c) All statements are correct.
d) Only statements 1, 2, and 3 are correct.