Which of the following is a cause of arterial spasm?

Arterial spasm is primarily influenced by various factors that can cause the smooth muscle within the arterial walls to contract suddenly. One of the significant causes of arterial spasm is exposure to cold temperatures. When the body is exposed to cold, the peripheral blood vessels constrict as a physiological response to conserve heat. This constriction can lead to increased resistance in blood flow and, ultimately, result in arterial spasms. Such spasms can restrict the blood supply to various tissues, potentially causing symptoms such as pain or ischemia.

The other options provided may contribute to cardiovascular issues in different ways, but they are not direct causes of arterial spasm. Impaired circulation generally refers to chronic conditions affecting blood flow but doesn’t directly trigger spasms; dehydration can affect blood viscosity and flow but does not cause spasms specifically, and while infections can lead to inflammatory responses that might affect blood vessels, they don't directly induce arterial spasms like cold temperatures do.