A quantitative variable is the one who has a numerical significance such as number of items, time spent on playing a video game while a qualitative variable is the one who has not a numerical significance attached to it such as Gender , Eye color
Further in quantitative variable , discrete variable is the one which is a whole number and can not be broken down further , like number of items
while a continuous variable is the one which takes any value within an interval of values like between 1 and 2 , continuous variable can take any value like 1.21, 1.55556, 1.994 etc.
The daily number of customers in a store can take a whole number value.
Thus, the variable is discrete.