Nasdaq yesterday dropped Young Broadcasting, the parent of KRON-TV, from the stock exchange after it became a penny stock. Young said it is working to get its stock listed on the over-the-counter exchange. Young, which skipped a $6.1 million interest payment Jan. 15 on notes due in 2014, is struggling to reorganize and has been warning of a bankruptcy filing since November. Young owns nine other stations, all network affiliates in small- and medium-sized markets.