What is the optional footwear for women in service or dress uniforms?

The optional footwear for women in service or dress uniforms is a smooth or synthetic leather flat shoe. This type of footwear is designed to complement the formal nature of service or dress uniforms, maintaining a polished and professional appearance. Smooth or synthetic leather provides a sleek look, which is appropriate for the setting and reflects the standards expected in military or uniformed service environments.

The other choices, while valid types of footwear in different contexts, do not align with the formal requirements of service or dress uniforms. Sport sneakers are more casual and not suitable for formal settings. Heavy-duty combat boots are typically reserved for operational settings rather than ceremonial or formal occasions. Casual sandals lack the formality and structure needed for uniforms, making them inappropriate as an optional choice for such attire.