After Consistently Burning Dinner for a Month,John Found Out That

Multiple Choice

After consistently burning dinner for a month,John found out that his oven's temperature gauge was giving readings that were 50 degrees cooler than the oven's actual temperature.John's oven thermometer can be said to be:

A) valid but not reliable.
B) reliable but not valid.
C) neither reliable nor valid.
D) both reliable and valid.