What do you believe is the single most important factor driving up the cost of living in Nigeria?

Elon Musk showcased a robotaxi with two gull-wing doors and no steering wheel or pedals at a splashy event on Thursday and added a robovan to the roster as Tesla's TSLA.O goal shifts from low-priced mass-market automaker to robotics manufacturer.

Musk reached the stage in a "Cybercab" which he said will go into production in 2026 and be priced less than $30,000. He said operation will cost 20 cents a mile over time and charging will be inductive, requiring no plugs.

He said the cars rely on artificial intelligence and cameras and do not need other hardware such as what robotaxi rivals use - an approach investors and analysts have flagged as challenging both from a technical and regulatory stand point.

"The autonomous future is here," Musk said. "We have 50 fully autonomous cars here tonight. You'll see model Ys and the Cybercab. All driverless."

Musk also showcased a larger, self-driving vehicle - called Robovan - capable of carrying up to 20 people, and showed off Tesla's Optimus humanoid robot.

• Read More