The question starts with incomplete sentences. Beneath each sentence, there are four words/phrases marked a, b, c and d. Choose the one word/phrase that best completes the sentence.
A loudspeaker is an instrument _____ electrical energy into sound energy
আপনি আমাকে যেকোনো প্রশ্ন করতে পারেন, যেমনঃ
Are you sure to start over?