Office supplies of 900 were purchased on account to be used

Question

Office supplies of $900 were purchased on account to be used infuture months. One part of the accounting entry to record this event in the accounting system would be to:

1. increase assets by$900
2. decrease assets by $900
3. increase expenses by $900
4. decrease liabilities by $900

I think its increase expenses by 900 just not sure.