If payment to the parties (on which TDS has been deducted) has been made actually i.e. by cash, cheque, demand draft or any other acceptable mode, then "otherwise" has to be mentioned in the specified field. But if payment has not been actually made and merely a provision has been made on the last date of the accounting year, then the option "Paid by Book Entry" has to be selected.
Certificate for lower deduction or no deduction of tax is given by the Assessing Officer on the basis of an application made by the deductee. In cases where the Assessing Officer has issued such a certificate, deductor has to only mention whether no tax has been deducted or tax has been deducted at lower rate on the basis of such a certificate.
https://www.incometaxindia.gov.in/etds_faqs.asp