Please help me its very easy

experiments.

surveys.

questionnaires.

interviews.

case studies.

participant and non-participant observation.

observational trials.

studies using the delphi method.

acts of terrorism occur globally. the united nations global counter-terrorism strategy was created in order to build adequate systems of support and solidarity with victims of terrorism. here´s a summary of the proposed key themes: the importance of giving victims a face and a voice; protecting their dignity; giving victims legal status and defending their legal rights; providing victims with medical, psycho-social and financial support; building solidarity with victims; improving media coverage of victims; and focusing on the link between victims and counter-terrorism efforts more generally.

c. have a great

the answer is:

a. a closed question always has yes or no​ answers, whereas an open question is a​ free-response question.