business law question:

Do the following contracts need to be in writing to be enforceable? Explain why or why not. 1. A contract whereby the president of NewCo. Gives a personal guarantee (i.e., uses personal assets as collateral) for a $150,000 revolving line of credit loan to NewCo. From First National Bank 2. An agreement of sale for a piece of real estate for a corporation to build a new warehouse for $500,000. 3. A contract for consulting services for $10,000 over the next 90 days. 4. A two-year advertising contract between a retail store and a local newspaper