Final answer:
Mirabeau Lamar is most remembered for establishing the Texas public education system, which earned him the nickname "Father of Texas Education."
Step-by-step explanation:
Mirabeau Lamar is most remembered for his establishment of the Texas public education system. As the second President of the Republic of Texas, he was a strong advocate for education and set aside lands to fund it, earning the nickname "Father of Texas Education." While he did play roles in the Texas Revolution and had expansionist policies during his presidency, these are not as prominently remembered or celebrated as his contributions to education.
Therefore, the correct answer to what Mirabeau Lamar is most remembered for is (B) His establishment of the Texas public education system.