A tartlet shell can take which of the following forms?

Tartlet shells are versatile baked goods that can come in a variety of shapes, which enhances their presentation and adaptability for different fillings. The correct answer acknowledges that tartlet shells can be crafted in round, square, or rectangular forms, allowing for creativity and variety in both home baking and professional pastry work.

Using different shapes not only serves aesthetic purposes but can also cater to specific themes or presentations in desserts. For example, a round tartlet might be more traditional, while a square or rectangular one could be used for modern plating or to fit neatly into a gift box or a specific serving tray. The ability to use various molds and techniques opens many possibilities for pastry chefs, making this option the correct choice.