, flowers are described based on symmetry:

• Zygomorphic (bilateral symmetry): When a flower can be divided into two similar halves only in one particular vertical plane. Examples given are pea, gulmohur, bean, and Cassia.
• Actinomorphic (radial symmetry): When a flower can be divided into two equal radial halves in any radial plane passing through the centre. Examples given are mustard, datura, and chilli.
• Asymmetric: e.g., Canna.

Therefore, among the typical list (Mustard, Gulmohur, Cassia, Datura, Chilli), the zygomorphic flowers are Gulmohur (b) and Cassia (c).