。
Rice is sold in kilogram units.
Literal
Rice [topic-は] kg units [in-で] sold is.
Notice ｋｇ in full-width Latin letters — the standard form for SI unit abbreviations in Japanese text. The full-width letters match the visual width of Japanese characters. キロ in katakana is the alternative, more naturalized form. The passive 売られている marks rice as the topic with the ongoing-state ~ている for an established commercial practice.