Which of the quadratics has a graph with only one x-intercept

There may be one or even no x-intercepts, as we see below. When is there only one x-intercept? This happens when the factored form of the quadratic is a perfect square.

the rocket cannot penetrate the ground, in a contextual sense, therefore the roots of this equation should be the domain of this function. i'll let you find the roots of this quadratic equation (hint: use the quadratic formula:  

1- c

2-a

step-by-step explanation:

mark brainliest!