A portfolio manager begins his research process for each day's trades by running filters on all of the public traded companies in the world. These filters include P/E, price‐to‐sales, price‐to‐book. From there he begins to identify what countries and sectors these stocks are in. What type of investment strategy is this?

a. Top‐down
b. Bottom‐up
c. Sector rotation
d. Buy‐and‐hold