A site is available at a purchase price of GH$150,000$ and it is anticipated that planning permission could be obtained for a factory of $7500$ m$2$ or an office block of $17500$ m$2.$ The estimated cost of the factory including site works is GH$1,125,000$ and the comparable cost of the office block is GH$6,300,000.$ The contract periods are assessed at one year for the factory and two years for the office block. On completion the office block is likely to have an annual rental value of GH$875,000$ with the landlord's annual outgoings of GH$200,000.$ The normal return on office blocks in this area is $7$ per cent. The factory is likely to sell for GH$1,900,000$ on completion. Legal, agency and advertising costs are likely to be GH$60,000$ for the factory and GH$280,000$ for the office block. Architect's and surveyor's fees are $10$ per cent of construction costs and finance is at an advantageous interest rate of $12$ per cent. Determine the form of development likely to profit the developer most.