An effect of the Supreme Court's ruling in Scott v. Sandford was that

legal protection for slavery was strengthened.

legal protection for slavery was weakened.

the abolitionist movement was strengthened.

the Missouri Compromise was strengthened.

The correct answer is legal protection for slavery was strengthened.

Indeed, one of the first disastrous political consequences of the ruling is that the South hailed victory and stated that this ruling confirmed that the Constitution gave each state, whether in the North or South, the right to decide whether to authorize slavery or not and that Free States could not free a slave that had been brought in by a slaveholder from the Slave states without the consent of the slaveholder. In practice, this meant that slavery would be de facto legitimized in Free States. Furthermore, the decision greatly weakened the Missouri Compromise because slavery had precisely been forbidden in the Wisconsin territory by the said compromise. To make things worse, the Chief Justice Roger Taney even explicitly added an Orbiter Dictum (by the way, in Latin) comment that the Missouri Compromise was unconstitutional.

Answer: The correct answer is A