Source B is more credible because it is from a government site, so it is meant to inform. It has a quote that shows drones are in debate.
At first look, the sources seem similar. They both were written around the same period and the URL appears almost identical. However, it is important to notice that source A is from a website ending in ".net," while source B ends in ".gov." Government websites are always more credible than a website ending in ".com" or ".net." Also, source A has advertisements, which means it is mostly for entertainment. In comparison, source B has a quote from President Obama. Since the research is about the invention of drones and their controversial uses, source B is also more helpful since the title specifically mentions the rules and misuse of drones.
When visits the witches a second time, they say that only when Birnam wood marches towards the castle and only man not born of woman can kill him, it's like a confident boost because these things seem impossible.However, the woods look like they move as an army approaches Macbeth's castle, and Macduff (who he is warned of) was cut from his mother's stomach, not physically born.
Hope this helps!<span />
Can you please add more detail to the question ?