You may accomplish this by using two tables—basically, a summary table—one for input and the other for viewing. Then, all that would be required of your formula is an IF statement and a COUNTA.
You might try the following for the Formula in C2 in the summary table:
=IF(COUNTA('Input Table'!$B2:C2)<1,"?",'Input Table'!C2)
This calculation assumes that the page labelled "Input Table" contains the INPUT data in the same columns as the snapshot you provided.
The only difference is that you would extend the references in Cell D2:
=IF(COUNTA('Input Table'!$B2:D2)<1,"?",'Input Table'!D2)
Ideally though, as another contributor said though, the best way is VBA if you are able.