Explanation:

The world's largest aeroplane - Scaled Composites Stratolaunch - made its first test flight over the Mojave Desert in California. Hence option (b) is correct.

The aircraft has two fuselages and six Boeing 747 engines. The aircraft has the largest wingspan ever to fly, superseding the Hughes H-4 Hercules. It's wing span is longer than a football field, or about 1.5 times that of an Airbus A380. It can carry 550,000 lb (250 t) payload and has a 1,300,000 lb (590 t) maximum take-off weight. It is designed to carry into space, and drop, a rocket that would, in turn, ignite to deploy satellites.