If m is the mass of electron cloud, the equation of motion of electron cloud in the presence of an alternating electric field is of the form

• A. <img src="/_files/images/electronics-and-communication-engineering/materials-and-components/64-1.png">
• B. <img src="/_files/images/electronics-and-communication-engineering/materials-and-components/64-2.png">
• C. <img src="/_files/images/electronics-and-communication-engineering/materials-and-components/64-3.png">
• D. <img src="/_files/images/electronics-and-communication-engineering/materials-and-components/64-4.png">