Step 1: Recall the standard order of adjectives in English.
The general adjective order is:
\[
\text{Size} \rightarrow \text{Colour} \rightarrow \text{Material}
\]
Step 2: Classify the given adjectives. big — size
blue — colour
plastic — material
Step 3: Arrange according to the correct order.
\[
\text{big} + \text{blue} + \text{plastic}
\]
Step 4: Match with the given options.
This order matches option (C).
Hence, the correct answer is
\[
\boxed{\text{big blue plastic}}
\]