This should help look at the pictures?
Spring tides will occur during a full moon and an new moon. The sun and moon are on a certain angle causing these tides to be neap tides, they aren't high tide nor are they low tides so you would verbalize they are in between and that is why it is called neap tides as well.
A parsec is a measurement of distance.
the answer is c) the speed and direction of travel must be constant
