The correct option is B Liliaceae
Allium cepa is example of Liliaceae. In family Liliaceae - perianth and trimerous flowers are found. Both the petals and sepals are usually similar and appear as two concentric groups (whorls) of petals, that are often striped or multi-coloured and produce nectar at their bases. The stamens are usually in two groups of three (trimerous) and the pollen has a single groove (monosulcate). The ovary is placed above the attachment of the other parts.
Therefore, the correct answer is option B.