I believe the answer is: b. <span> Ennis alerted his superiors to the existence of secret evidence but, when they ignored it, Ennis did not make the evidence public. He remained silent.
Withholding information usually is not the actions that taken by the honest individuals. Ennis actions indicate that He could receive something from the superiors that make him feel justified to stay silent rather than showing all the evidence to the public.</span>
There are 4 conditional waves of Russian immigration to the United States.
The first was connected with the Russian development of America in the 18th-19th centuries and was represented by small Russian researchers who founded settlements along the Pacific coast.
The second took place at the turn of the 19th and 20th centuries and was represented by Jews from the Russian Empire.
The third - a small wave - was represented by political emigrants (mostly also Jews) from the USSR in the late 60s and early 70s.
And, finally, the most massive influx (the fourth wave) occurred during the fall of the Iron Curtain in the late 1980s and early 1990s, when numerous groups of Jews, Russians, Ukrainians and others arrived (mainly already at the turn of 20-21 centuries).
