Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to buy citric acid [title] Determine how much citric acid you need to buy. [step] The amount you need will determine where you should shop for citric acid. Smaller quantities can generally be purchased at the grocery store, while larger quantities may need be purchased at a bulk store or online.

Ending1: [substeps] Skip fruits like apples and peaches as they do not have a lot of moisture and will take longer to mature. Leafy greens like cucumbers and bell peppers can make for an excellent source of citric acid. Ending2: [substeps] In most books and websites, you can find information about where you need to purchase citric acid. If the quantities you are looking for are not available at the grocery store, ask friends or fellow customers. Ending3: Note that the citric acid you use will vary by brand, so you may need to look through different brand's store identifiers before making a final choice. As for the quantity, just carry a ballpoint pen with you. Ending4: [substeps] Consult the instructions for your activity or recipe to see how much citric acid they indicate you need to use for your project. Increase the amount of citric acid if you plan to make multiple batches of a recipe or want to have an ample amount for repeating the activity.

Answer format: ending1/ending2/ending3/ending4