Copy Data One Workbook to Another

Hello guys, I am a new to excel. Still learning. Please help me solve a problem. Thank you in advance.

COULD YOU PLEASE SOLVE:

CONSIDER 3 CELLS: A2,B2,C2 in a Workbook named, Data Entry.

A2 is where I write data in.
B2 is a drop down list of 3 different posting workbook's named: X, Y, Z.

I want a SAVE button.
When SAVE button is clicked, I want to copy cell A2 to the workbook chosen from the drop down lists in B2. If X is chosen, data will save in X workbook only.

I hope this makes sense. And expect to see wonderful solution from you guys.
Thanks once again.