As you present your speech, you notice that many of your listeners have interested looks on their faces and are nodding their heads in agreement with your ideas. according to the video, these reactions by your listeners are

Feedback.

Explanation:

Noticing that, when giving a speech, many listeners are nodding in agreement (in this case, they could very well be shaking their heads in dissaproval), is a signal that is interpreted as positive. Every signal, unconscious or otherwise, be it a direct response or not, could be interpreted as feedback: a reaction, a response, a devolution. In this case, it's positive, as many listeners are nodding in agreement. But in a class context, for example, feedback could be given at the end of the speech to list things to improve, to acknowledge things that went well, etc etc.

im sorry i wish i can but try google

the correct answer is a