Answer:
C) Number of people in a room is a discrete data.
Explanation:
Discrete Data is defined as the data than can only take certain values.
The values in the discrete data can not be continuous.
Now,
A) Height of a tree : A tree can be of any length and hence is NOT a discrete data.
B) Time Taken to change a bulb : This time taken to change the light bulb may vary from person to person. Hence it is NOT a discrete data.
C) Number of people in a room: This is a discrete data as the number of people can not be in fractions.
D) Weight of a baby : This is NOT a discrete data as the weight of a baby may vary with time. It can increase and decrease with time.