Correct Answer: Monogamy

Solution : The correct answer is the first option.

Monogamy is a noun that describes the practice or state of being married to one person at a time. The term monogamy accurately captures the concept of being married to a single person at any given time, aligning with the grammatical requirement and the specific meaning sought.

The meanings of the other options are as follows:

• Bigamy : The word refers to the act of marrying one person while still legally married to another, involving multiple marriages.
• Polygamy : The word refers to the practice of having more than one spouse simultaneously, indicating multiple marriages.
• Homogamy : The word refers to the tendency of individuals to marry others with similar social characteristics.