how to select top 3 OR top 5 from Column

Question

Hi All

I have Table with this values

 

Name_student             Mark

Ahmed                         200

Naser                           200

Tom                             150

Jaber                           100

Mohammad                70

Khaled                         60

Radwan                       50

 

I want to select top 3 students by Marks 

lilk this

 

Name_student      Mark

Ahmed                  200

Naser                    200

Tom                      150

Jaber                     100 

 

how to do that ?