Given:

Bar graph for various sports played by several students.

To find:

Difference between the number of students playing football and cricket.

Calculation:

The bar graph represents different sports played by several students.

It can be observed from the bar graph that, 

Number of students playing Cricket=50

Number of students playing Football=45

$\Rightarrow$Difference between the number of students playing Cricket and Football = Number of students playing Cricket - Number of students playing Football

    = 50 - 45

    = 5

Therefore, option A is the correct answer.