OLAP$/$BI tools can be used for:

A$.$ Ad$-$hoc direct analysis only

B$.$ Creation of front$-$end $($BI$)$ applications only

C$.$ Ad$-$hoc direct analysis and creation of front$-$end $($BI$)$ applications

D$.$ Neither ad$-$hoc direct analysis nor creation of front$-$end $($BI$)$ applications