B. The Soviets were embarrassed
because despite their technological successes, people were fleeting in large numbers
How was it inferred that they were embarrassed not just because people were fleeting in large numbers but because even after technological success, people were fleeting in large number. I feel there is no connection being made between technological success and feeling of embarrassment
Excerpt from passage - For the next three years, the Soviets emboldened by the successful launch of the Sputnik satellite the year before and embarrassed by the seemingly endless flow of refugees from east to west (nearly 3 million in the decade since the end of the blockade, many of them young skilled workers such as doctors, teachers and engineers) blustered and made threats, while the Allies resisted.