How do I know (by looking) which notes are higher-sounding pitches or lower-sounding ones?

A. The higher up the circle note head is printed on the staff (on the page), the higher the sounding pitch.

B. If the stem of the note points up, it's a higher-sounding pitch.

C. Half Notes sound higher than the other kinds.

D. “Line Notes" always sound higher than "Space Notes".

a says if the circle part of the note on the staff is at a higher space or line than another, it is a higher pitch. since thats true, this is the correct answer :).

its not b because, for example, a b note on the a string for a violin is higher than an f on the d string yet the b has a line pointing downward but the f has a line pointing upward. the notes with stems going downward are actually almost everytime higher than notes with the stem going up. so this one is wrong.

its not c cuz half notes do not change the pitch of the note, only the amount of time you stay on that note so that ones wrong too.

its also not d becuse notes on a line of the staff are just a different note than ones on a space. the lines and spaces have nothing to do with the pitch of a note, just what note it is. not all lines are higher than spaces and not all spaces are higher than lines. the pitch goes up as you go upward on the staff so the lines and spaces alone dont have a direct impact on the pitch.

so the answer is A

I hope this helped :))