Reaching the initial target may be a stretch because some interior suppliers might not be able to increase the flow of high-quality parts fast enough to meet the Model X production plan, chief executive officer Elon Musk said on a conference call with analysts.
Take context from the input text and decide on the accurate relationship between 'Elon Musk' and 'chief executive officer' from the options provided.
Options: position held, subsidiary, owned by, developer