Answer:

Step-by-step explanation:
Active Voice: An action or doing that is currently happening
Passive Voice: An action or doing that has already happened
Sentence: Our old toaster always burns the toast on one side
This sentence is in the 'Active Voice'. We know this because the sentence did not use words such as "was, did, happened", etc. The sentence takes place when the toast had just gotten burned.
Sentences A, B & C: These sentences contain the word "was". 'Was' is 'Passive Voice.' Meaning, it already happened. It is not currently happening, whereas sentence D is happening right now.