Plz asap im on the test now which sample is biased? a. interviews of random teenagers who attended a rock concert to find out which musician teens enjoy most. b. a poll randomly surveying half of the students in grade 7 to find out which seventh-grade teacher at the school is most liked. c. an online survey by a game development company taken after the game closes to find out which features of a new game players liked the most. d. a questionnaire delivered to two employees from every department of an office to find out whether employees like the new coffee machine.

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?