Which one of the following equations represents parametrically, represents equation to a parabolic profile?
a. x = 3 cos t; y = 4 sin t
b. x² - 2 = 0cos t; y = 4 cos² t/2
c. x = √1-sin t; y = sin t/2 + cos t/2
d. √x = tan t; √y = sec t