The correct option is B Tetradynamous stamen - Mustard
The stamen of mustard is tetradynamous where out of six stamens, two are shorter than the four.
Cassia has imbricate aestivation where the margins of sepals or petals overlap one another but not in any particular direction.
The stamens of china rose are monoadelphous where the stamens are united into one bunch or one bundle.
Cucumber is a monoecious plant where the male and female flowers are present on the same plant.