A bag has 4 red balls and 2 yellow balls. (The balls are identical in all respect other than colour). A ball is drawn from the bag without looking into the bag. The probability of getting a red ball is __.

• A.  \[\frac{1}{2}\]                                   
• B.         \[\frac{2}{3}\]           
• C.         \[\frac{1}{4}\]                                   
• D.         \[\frac{1}{5}\]