Which of the following represent a wave equation for a tightly stretched elastic string of length l and 'm', mass per unit?

• A. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/1-744-12-1.png">
• B. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/1-744-12-2.png">
• C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/1-744-12-3.png">
• D. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/1-744-12-4.png">