The correct answer is option 'B' - Malvaceae.

Monothecous condition of stamens:

Monothecous condition refers to the presence of a single anther lobe in the stamen. In plants, the stamen is the male reproductive organ that produces pollen grains. The stamen typically consists of a filament and an anther. The anther is responsible for the production and release of pollen. In some plant families, the anther may have more than one lobe, while in others, it may have only a single lobe.

Characteristics of Malvaceae family:

The family Malvaceae, commonly known as the mallow family, includes several genera of flowering plants. Some of the key characteristics of this family include:

1. Monothecous condition of stamens: One of the distinctive features of the Malvaceae family is the presence of stamens with a single anther lobe. This means that each stamen in this family has only one lobe or compartment within the anther.

2. Pentamerous flowers: The flowers of Malvaceae are typically radially symmetrical and have five sepals and five petals. These flowers are often large and showy.

3. Epicalyx: Malvaceae flowers are often surrounded by an additional set of small bracts called the epicalyx. The epicalyx is located just below the calyx and may resemble a second calyx or form a whorl of bracts.

4. Superior ovary: The ovary of the flower is positioned above the attachment point of the other floral parts, making it superior. The ovary develops into a fruit after fertilization.

5. Presence of mucilaginous substances: Many species in the Malvaceae family produce mucilaginous substances, which give them a slimy or gelatinous texture. These substances often have medicinal or culinary uses.

Conclusion:

Based on the given information, the monothecous condition of stamens, i.e., the presence of a single anther lobe, is a characteristic feature of the family Malvaceae. The Malvaceae family includes various plants such as hibiscus, cotton, okra, and marshmallow.