Generate a colum by combining two other columns

Hello,

I want to know if there is a way for me to combine two columns in a way that each cell on the first row is concatenated with each item of the second column.

For example in the below case, I would like to generate column C to be A1,A2,A3,B1,B2,B3,C1,C2,C3 

Is there anyway I can do this?