In such types of questions, mention the things which motivate you to work for the company. Try to highlight the values and the motto which the company believes in as PART of your MOTIVATION to join the company. 

The following could be a sample answer:

“I'd like to work with IBM because IBM has a strong set of principles and a clear commitment to not only your staff but also to your customers and clients. This is an organisation where I will be ABLE to GROW, thrive, and develop over time, and I will have the opportunity to work with an incredibly brilliant group of PEOPLE who are all dedicated to the IBM brand's long-term success. I see this as a once-in-a-lifetime opportunity to put my abilities and traits to good use.”