What type of secretion does the sublingual gland primarily produce?

The sublingual gland primarily produces mucous secretion, which is its main type of secretion. This gland is one of the major salivary glands and is located beneath the tongue. While it does have some serous components, the predominant secretion is mucous, which plays a crucial role in lubrication and helps with the initial digestion of food.

In this context, the other choices would not accurately represent the primary nature of the sublingual gland's secretion. The focus on mucous production aligns with the functional needs of the oral cavity, as the slippery mucus aids in the swallowing and movement of food. While some glands can produce both types of secretions, the sublingual gland is distinguished primarily by its mucous output, thus making the option of "both serous and mucous" less precise regarding its main function.