B for the first one.
A strengthens the speculation.
B weakens the argument. If the prey is incapable of hearing/perceiving the sound, it can't be stunned.
C is tempting, but it discusses the effect in "far away prey". The text talks about stunning the prey which is nearby.
D can be discounted easily.
E can be discounted easily.
C for the second one. If the company sells more coffee that any other company in the world, it might be using less percentage of the columbian coffee in its blend than the others use.
for every person who doesn't try because he is
afraid of loosing , there is another person who
keeps making mistakes and succeeds..