"a researcher is conducting an experiment to test four different executions of an advertisement. each subject is exposed to one of the ads and then asked to complete a questionnaire assessing their attitude toward that ad and brand advertised. while there are four different executions of the ad being tested, each subject is exposed to one ad only. what type of experimental design does this represent? "

Between-subjects design.

Explanation:

The experiment illustrated here characterizes the "Between-subjects design" experiment. It refers to a type of experiment that is inclined towards the examination one condition by different people, so that every person is defined to single interface. This method is applied to observe reaction by applying same variations of conditions to every subject that helps to reduce the chances of contamination of the experiment. Similarly, in the given experiment the researcher has exposed one of the ads to be experimented where each subject is disclosed to one ad only. Thus, this study is aimed to observe the reactions and impact of four different executions that reflects 'between-subjects design'.

showing or suffering from nervousness, fear, or a lack of confidence

i think it's either 'to expose the corruption of the communists in russia', or 'to criticize animal brutality by communists in russia.'  

hope this ! : )