<prompt> Most common organism causing community acquired pneumonia -Staphylococcus aureusStreptococcus pyogenesStreptococcus pneumoniaeHaemophilus influenzae  <response>: Ans. is c i.e., Streptococcus pneumoniae o Streptococcus pneumoniae is the most common cause of community acquired acute pneumonia. It is the most common cause of lobar pneumonia. 