In analyzing a particular corpus, the following information is provided: Term t Kangaroos Total # documents $150$ # docs containing t $23$ TF for t in document d $5$ Which of the following is true? Notes: Use log to base $10$ to calculate IDF In analyzing a particular corpus, the following information is provided: Which of the following is true? Notes: Use log to base $10$ to calculate IDF

$[$ IDF$($t$)=1$; IDF$($t$)=-3$; IDF$($t$)=1\mathrm{.}81$; IDF$($t$)=2\mathrm{.}5]$