Write the floral formula of a mustard flower and provide its floral diagram.

(N/A) The mustard plant belongs to the family Brassicaceae. Its floral formula is represented as:
$\oplus \, \text{O\kern-0.4em\raisebox{0.3ex}{+}} \, K_{2+2} \, C_4 \, A_{2+4} \, \underline{G}_{(2)}$
Explanation of symbols:
- $\oplus$: Actinomorphic (radially symmetrical)
- $\text{O\kern-0.4em\raisebox{0.3ex}{+}}$: Bisexual flower
- $K_{2+2}$: Calyx with $4$ sepals in two whorls
- $C_4$: Corolla with $4$ petals
- $A_{2+4}$: Androecium with $6$ stamens in two whorls (tetradynamous)
- $\underline{G}_{(2)}$: Gynoecium with $2$ fused carpels,superior ovary