For ALL Questions in this exercise, please use the North American Stock Market 1994-2018 dataset. Please load the data into a data frame called companies by reading the appropriate.rds file. See lecture slides to see how to do this. Make sure to run the code library(tidyverse) so you load tidyverse. For each fiscal year (fyear), you want to calculate the median value of assets (at) for all companies recorded in that fyear. Make the assumption that each company is listed only once per year. Which fyear had the highest median at? 2001 O 2009 O 2011 2018 O None of the above. Suppose you want to create a new dataset. To create this new dataset, start with the usual companies dataset. Then, for each firm, drop all observations (of that firm) if the firm has never reached $100 million in total assets (i.e., at) at any time in the dataset. Note that assets is listed in millions, so $100 million would be 100. To elaborate, let's consider the following hypothetical case: Suppose there are 6 observations for company ABC. If at least one of these 6 observations has at >= 100, you must NOT drop ANY of the observations for firm ABC. How many observations (i.e., rows) are in the new dataset after dropping observations indicated above? Hint: Each company is uniquely identified by its gvkey, and each row is uniquely identified by the combination of gvkey and fyear. O 9,003 O 144,655 O 163,777 O 177,391 O None of the above. Now, start with the full companies dataset again. Suppose you want to drop any observation (i.e., any row) that has less than $100 million in total assets (at