which event has a probability of 1

Be more specific

ok....thats the question tho and would you like da options

Yes

ok....................they r

A.flipping heads on a two-sided coin

B.rolling an even number on a six-sided number cube

C.choosing a red or blue marble out of a bag full of red, and blue marbles

D.spinning blue on a spinner that has equal number of red, and yellow spaces

A is not right.

An event that has a probability of 1 is called a certain event. It means that the event is guaranteed to happen and there is no chance of it not occurring. In other words, the event is always true.