Nonmetals and negative. Answer is c
Low pH = high acidity.
HF has a very low pH, so when added to a solution, it will lower the pH of the solution and therefore make it more acidic. So the answer should be B.
I believe in what USA was and is able to achieve, and trust the nation in many but every ways. What really made it a developed nation is the things that happened in the last 3 Centuries, some of which are;
#1 CULTURAL TOLERANCE & IMMERSION
#2 TECHNOLOGICAL INVENTIONS & ADVANCEMENT IN THE FIELD OF SCIENCE
#3 FAST FOOD CULTURE
#4 HOLLYWOOD
#5 INTEGRITY & PATRIOTISM
#6 MASS CONSUMERISM