Final answer:
The highest weekly average price for gasoline in California during 2005 was $3.15 per gallon.
Step-by-step explanation:
The highest weekly average price for gasoline in California during 2005 was $3.15 per gallon.
To determine this, we need to compare the average prices of gasoline in each week of 2005. The highest price among the given options is $3.15 per gallon, so that is the correct answer.