Assuming that you are holding the land as fixed asset in the books of firm on which you intend to develop and sell commercial offices and showrooms. The fact that you intend to develop and sell the commercial spaces itself establish that you are intended to enter into a venture in the nature of trade and business. Therefore the income earned from these activity will squarely be covered under the 'Business Income' and not 'capital gains'. However in respect of Land, you may compute capital gain or business income by converting the same into stock-in-trade as per section 45(2).