Final answer:
The correct equation representing Olivia's height is x = y + z + 7, where x is Olivia's height and y and z are the heights of Emma and Liam, respectively.
Step-by-step explanation:
The question asks which equation represents Olivia's height if her height is seven cm more than the sum of the heights of her friends Liam and Emma.
The correct choice is C) x = y + z + 7; x represents Olivia's height, y represents Emma's height, and z represents Liam's height. This option correctly shows Olivia's height as the combined heights of Emma and Liam plus an additional seven cm.