The correct option is 50.

To find the missing number, we need to determine the relationship between the first and second numbers in the given pairs.

Let the first number in a pair be $A$ and the second number be $B$.

Let us analyze the relationship in the first pair:
19 : 34
If we multiply the first number by 2 and subtract 4, we get:
$B=(19\times 2)-4=38-4=34$

Let us verify if this same pattern holds true for the second pair:
5 : 6
Applying the same operation:
$B=(5\times 2)-4=10-4=6$

Since the logic is consistent, we can apply it to the third pair to find the missing number:
27 : ?
Using the same relation:
$B=(27\times 2)-4=54-4=50$

Thus, the number related to 27 in the same way is 50.