Correct answer: B. He increased the influence of nobles, which made the monarchs more powerful.
After ascending to the throne of France, Henry IV made an effort to visit the provinces and establish relationships with the nobility in the territories which they governed, to establish connections with him and his central government. Henry also made it a practice to offer well-to-do bourgeoisie the ability to purchase a government office in his administration, which came with the title and advantages of nobility (like tax exemptions). This not only raised some immediate revenue for his rule, but also tied those "nobles of the robe" to his government in their loyalties, because their status as nobles depended on him.
As to answer A: Yes, Henry IV worked to build roads, improve agriculture, and administer justice for the betterment of France and to build the loyalty of the people to his rule. But under Henry IV's rule, the central government did not control "almost every aspect of life." He worked hard to consolidate and centralize power for his government, but he was not yet what we would call an "absolute" ruler.
As to answers C and D: He did make improvements, as noted in my previous comment.
