Spring tides--
Select one:
a. occur at new and full moons, and have the highest high tides and lowest low tides.
b. occur at first- and third-quarter moons, and have the lowest high tides and highest low tides.
c. occur at new and full moons, and have the lowest high tides and highest low tides.
d. occur at first- and third-quarter moons, and have the highest high tides and lowest low tides.