Pls help me with questions number 4

[ou.01jthe greatest speed with which any physical object moves is 300,000 km/soundsec. which of the following has a speed of 300,000 km/sec? a.light in water b.light in vacuum c.sound in air. d. sound in water

Which of the layers of the earth has the following three characteristics? i. it is a solid outer layer. ii. it is between 3 and 30 miles thick. iii. it is separated into plates. a. the outer core b. the inner core c. the mantle d. the crust

Based on what you know about speed of light and sound, which come/comes first in a thunderstorm