Answer:
D. Lonnie Smith filed a challenging lawsuit to primary system of races used by democrats to advance the cause of civil rights for African Americans in Texas.
Step-by-step explanation:
Lonnie Smith, a dentist by profession, was closely associated with the civil rights movement in Texas and was also a part of the National Association for the Advancement of Colored People. It was he who raised his voice against the all-white primaries in Texas and filed a lawsuit in the Supreme Court.
It was after the Supreme Court passed the judgment in the favor of Lonnie Smith the blacks got the right to vote in Texas.