Answer: Option 'A' is correct.
Step-by-step explanation:
Since we have given that
Length of Julian's shadow = 6 feet
Height of tall building = 31 feet
Length of shadow of building = 28 feet
Let Height of Julian be x
Since there is direct variation between height and shadow,so
Required proportion will be

Now, we'll calculate the value of x i.e. height of Julian,

Hence, Option 'A' is correct.