Which of the following is an indication that there is a bedbug infestation?

The presence of excrement spots and blood stains on sheets is a definitive indication of a bedbug infestation. Bedbugs are small, parasitic insects that feed on human blood, typically at night. After feeding, they often leave behind small rusty or reddish-brown stains, which are blood spots, on bedding or linens. Additionally, their fecal matter appears as dark spots or speckles on sheets and mattresses, further indicating their presence in an area.

In contrast, indications such as the presence of spider webs and moths can point to different pest issues and do not correlate specifically with bedbug infestations. Frequent scratching and allergic reactions might suggest potential responses to multiple types of pests or allergens and are not definitive signs of bedbugs alone. Unpleasant odor and discolored furniture could indicate other pest problems or damage but do not provide the direct association with bedbugs that the presence of blood stains and excrement does. Thus, the identification of these particular marks is essential in confirming a bedbug infestation.