Detailed Instructions: In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.
Q: Question: Which company has been in business the longest out of Booking Holdings and Expedia Group? Passage:Booking Holdings and Expedia Group, both online travel agencies, are the largest travel agencies on the list of top earning travel companies. Travel agencies can be multinational companies, referred to as "multiples" in the United Kingdom. They can also be medium-sized organizations, referred to as "miniples" in the United Kingdom, or can be independent, small companies. They can be structured as a limited liability company, a sole proprietorship, or can be set up as a host, franchising, or consortium structure, such as in the case of CWT. A traditional travel agent may work for a travel agency or work freelance. Helloworld Travel is an example of a franchised travel agency, giving agents access to internal systems for product and bookings. While most point-to-point travel is now booked online, traditional agents specialize in niche markets such as corporate travel, luxury travel, cruises, complicated and important trips, and specialty trips. Other niche markets include travelers with disabilities, travelers over the age of 60, women traveling alone, LGBT tourism, the needs of residents in an upmarket commuter town or suburb, or a particular group interested in a similar activity, such as a sport. Examples include StudentUniverse and STA Travel, which specialize in youth travel, or CWT, which caters to corporate travel. Many use telecommuting to reduce overhead, and/or provide concierge services. Agents can act as "travel consultants" with flawless knowledge of destination regions and specialize in topics like nautical tourism or cultural tourism. Many traditional agents prefer the term "travel advisor" as opposed to "travel agent" to emphasize their advice, expertise, and connections that are of great value. Outbound travel agencies offer multi-destinations; inbound travel agencies are based in the destination and deliver an expertise on that location.
 Links: a. Nautical tourism b. Expedia Group c. Consortium d. Nautical tourism
A:
b