Check your 1099-B statement. Review the interest income detail in the statement. Usually, your investment statement will detail how much interest was paid by the bonds from each state. You may be able to determine how much of the assets include California bonds or US Government bonds. If the number of California or US Government bonds in the mutual fund is less than 50%, answer Yes to this question. This determines if your interest will be taxable in California.
If you are unable to find the answer to this question, contact the mutual fund company. They are familiar with this topic and can easily assist you with this question. Or, you could visit the website of your mutual fund to find a percentage of California bonds and other assets in the portfolio.