When might you lock a layer? a. when you want to completely delete the layer b. when you want to remove all of the objects on the layer c. when you want to make sure you don't make any changes to the layer d. when you want to make the layer invisible, so you can't see it

C. When you want to make sure you don't make any changes to the layer

Explanation:

    Blocking a layer in graphics software is useful when you have accumulated a large number of layers. With a heavily edited project, you can be sure that you cannot change a layer by locking it. You can choose to fully or partially lock a layer using the four buttons found after "Lock" near the top of the Layers box.