Explanation

Gossypium arboreum is a diploid species (2n=26), but Gossypium hirsutum and other commercial cottons are tetraploid. However, the question likely refers to the genus or common confusion. Wait, Gossypium arboreum is indeed diploid. Let me double-check. Actually, Gossypium arboreum is a diploid species (A genome). Gossypium hirsutum is tetraploid (AD genome). The question asks specifically about Gossypium arboreum. So B is correct. Wait, sometimes questions have typos like 'Gassypium arborium' for Gossypium hirsutum? Or maybe it's a trick. I will stick with B being correct for arboreum. But let's verify standard MCQs for this. Often, commercial cotton (hirsutum) is tetraploid. If the question meant hirsutum, it would be A. Given the typo 'Gassypium arborium', it might be a poorly recalled question. I will mark it as correct but note the typo. Actually, Gossypium arboreum is diploid. So B is correct. I will output true.