What are the three different types of buying situations faced by a typical business buyer?

What will be an ideal response?

The business buyer faces many decisions in making a purchase. Three types of buying situations are the straight rebuy, modified rebuy, and new task.
Straight rebuy- In a straight rebuy, the purchasing department reorders supplies such as office supplies and bulk chemicals on a routine basis and chooses from suppliers on an approved list. The suppliers make an effort to maintain product and service quality and often propose automatic reordering systems to save time. "Out-suppliers" attempt to offer something new or exploit dissatisfaction with a current supplier. Their goal is to get a small order and then enlarge their purchase share over time.
Modified rebuy- The buyer in a modified rebuy wants to change product specifications, prices, delivery requirements, or other terms. This usually requires additional participants on both sides. The in-suppliers become nervous and want to protect the account. The out-suppliers see an opportunity to propose a better offer to gain some business.
New task- A new-task purchaser buys a product or service for the first time (an office building, a new security system). The greater the cost or risk, the larger the number of participants, and the greater their information gathering, the longer the time to a decision.