Which of the Following Statements About the Response of Arteriolar $\mathrm { P } _ { \mathrm { o } _ { 2 } }$

Which of the following statements about the response of arteriolar smooth muscle to changing oxygen partial pressures is true?

A) Both systemic and pulmonary arterioles respond to a decrease in by constricting
B) Both systemic and pulmonary arterioles respond to a decrease in $\mathrm { P } _ { \mathrm { o } _ { 2 } }$ by dilating
C) Systemic arterioles respond to a decrease in $\mathrm { P } _ { \mathrm { o } _ { 2 } }$ by dilating but pulmonary arterioles constrict in response to decreased $\mathrm { P } _ { \mathrm { o } _ { 2 } }$
D) Systemic arterioles respond to a decrease in by constricting but pulmonary arterioles dilate in response to decreased $\mathrm { P } _ { \mathrm { o } _ { 2 } }$
E) None of the choices are true