Explanation:

T = Tea
C = Coffee
n means number
n(T) = 30
n(C) = 20

Universal = 50

n(T U C)' = 6 , T union C complement (people who like to drink neither)

Let n(T Π C) i.e. T intersection C (People who like to drink both) = x

n(T) + n(C) - n(T Π C) + n(T U C)' = 50
30 + 20 - x + 6 = 50
56 - x = 50
- x = 50 - 56
-x = -6
x = 6

Therefore people who like to drink BOTH Tea and Coffee are 6.

People who drink coffee = 20
Thus, People who ONLY drink coffee = 20 - 6 = 14 people

Hence, option 1 is the correct answer.