Final answer:
The statement that Cream of Tartar is an optional ingredient when making meringue is true. Cream of Tartar helps to stabilize egg whites and prevent sugar crystallization, but it is not essential for creating a successful meringue.
Step-by-step explanation:
Cream of Tartar is indeed an optional ingredient when making meringue. The statement is true. Cream of Tartar, also known as potassium bitartrate or potassium hydrogen tartrate, is often used in baking and in making meringues as it can help to stabilize egg whites and create a firmer, more structured peak. However, it is not an essential ingredient for creating meringue. Many recipes for meringue do not call for Cream of Tartar and still produce a suitable outcome. The ingredient can be particularly useful in helping to prevent crystallization of sugar and to produce a more consistent texture, but other factors like egg white temperature and the speed of whipping can also be influential in the success of a meringue.