Kiara made a diagram to show the heights of the students.

Students' Height ( in meters) 

Student 1 - >  $5\frac{3}{4}$

Students 2 - > $3\frac{3}{8}$

Student 3 -> $8\frac{1}{3}$

Student 4 -> $2 \frac{14}{24}$

Which student's height is more than 7 ½ meters?

As we can see all the heights are given in mixed fractions.

We need to convert them into a simple fraction 

Student 1=  $5\frac{3}{4} = \frac{23}{4}$

Student 2=  $3\frac{3}{8} = \frac{27}{8}$

Student 3=  $8\frac{1}{3} = \frac{25}{3}$

Student 4=  $2\frac{14}{24} = \frac{62}{24}$

To compare the fractions we need the denominator to be the same, that means we need like fractions as we have unlike fractions so we get a GCF( greatest common factor) and multiply each one so we get the same denominator. 

In this case, the GCF is 24 

Student 1= $\frac{138}{24}$

Student 2=  $\frac{81}{24}$

Student 3=  $\frac{200}{24}$

Student 4=  $\frac{62}{24}$

Now as we got all of them in like fractions, we look at the question and it says what height is more than 7 ½ so we convert this mixed fraction into a simple fraction and convert

This mixed fraction into a simple fraction and convert into a like fraction to compare. 

Mixed fraction = $7\frac{1}{2}$

Simple fraction=  $\frac{15}{2}$

Like fraction=  $\frac{180}{24}$

So from comparing we can see that student 3 is taller than $7\frac{1}{2}$ meters.

Hence, option C is the correct answer.