Others are an easy elimination. Between B and E - "require for" is a commonly used idiom (thus, we may fall into the trap)" as the "firm's" is possessive as against what we need is "firms." B has it, but being a non-native speaker, sometimes it is difficult to choose a wired-looking option - I'll say if you don't know something - maybe it is because you did not hear it. It may not necessarily be wrong. For non-native speakers, do a ton of quality reading. GMAT (or, for that matter, any other quality exam such as CAT in India) punishes the attitude of just relying on your ear. Now, back to the key point in our question
1. "require for" usage - It indicates something necessary or essential for a particular purpose or outcome. It suggests that a certain condition or qualification is needed to achieve a specific goal or fulfill a certain requirement.
E.g., A bachelor's degree is required for this job position. A valid ID is required for entry into the concert venue.
2. "require of" usage - It is used to express a demand or explanation placed on someone or something. It implies that someone is asking or expecting a specific action, behavior, or quality from another person or entity.
E.g., I require of you to complete the assignment by tomorrow. The job requires of its employees a high level of attention to detail. The coach requires of the team to attend practice regularly.