Since empirical science always requires observation and all observations are made by individual observers, can the results of observation ever be objective or are they necessarily relegated to subjectivity, lying in the eye of the beholder?

The correct answer to this open question is the following.

You forgot to include the options of the question. However, we can answer the following.

Most of the time, the results of observation have to be objective, but one way or the other these are biased due to the subjectivity of the observer.

When scientists are doing research, they know that direct observation has its difficulties because people observe things from their own perspective. It is difficult to maintain 100 percent objectivity because we observe according or influenced by our own belief systems and knowledge. And that can distort the way we observe and conclude about people or events.

couples could only have one child to reduce the population growth.

that is probably something for you to answer