This depends on who you identify as the target market. Take into account both direct and indirect competitors.

Direct competitors

Direct competitors are things that do the same job as your product in much the same way as your product

Ford, Peugeot-Citroen, Renault, and Jaguar are direct competition

Indirect competitors

Indirect competitors are things that do the same job as your product in a different way to your product

In London, the Underground, overground, busses, taxis, and hire bikes are all indirect competitors because they all enable people to move around the capital more quickly than on foot, and with ease

Research (using solid academic sources) to determine who your in/direct competitors are

Which are the key/main competitors?

You must say which of the competitors identified are our main competitors

They may or may not be the market leader

They may not even be in our market at the moment – for example, Microsoft has tried (and failed) to introduce mobile handsets – they may want to try again. Likewise, Amazon seem to be trying to be ‘all things to all men’ so perhaps handsets will be their next thing? Answers should justify why companies identified are felt to be key competitors, using referenced research to support the answer