Answer:
b
Explanation:
Because the population is too large and it would be impractical to survey the whole population, a sample of the population is chosen to take part in the survey. This sample is taken as been representative of the whole population
Based on the sample, the fraction of students that speak more than one language fluently = 15/90= 0.166667
Population that would speak more than one language fluently = 0.166667 x 1800 = 300