Answer:
A) Was
Step-by-step explanation:
The main difference when using was and were is whether the subject was plural or singular. When using was, the subject is singular. When using were, the subject is plural
For example, the sentence, "___ she at school today?" would use was because "she" is singular. This sentence should read, "Was she at school today?"
Next, the sentence, "___ they at school today?" would use were because "they" is representing multiple people and is therefore plural. The sentence should read, "Were they at school today?"
Looking back at our original sentence, "milk" is the subject and is a singular noun. This means the sentence needs to use "was." The final sentence will read, "Was there milk in the fridge?"