Answer:
contaminated
Explanation:
The word fouled is used in the "The grapes of wrath"
where in writer says that "the water fouled the ignition wire and water fouled the carburetors".
In this context fouled means that some impurity is being added to the carburetor and wire frames.
Hence the best suitable word from the option will be "contaminated".
Contamination means " the act of making anything impure "