This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infeility (Eggs'plantation!), Subject name: Gynaecology & Obstetrics
Which of the following findings characterize lower reference limits in a normal semen sample? 
Select and explain. 
A. Volume >2ml, B. Sperm concentration of 40 million per mL, C. 30% normal sperm morphology, D. 32% progressive sperm motility
D: 32% progressive sperm motility
Answer: D: 32% progressive sperm motility 
Explanation: The WHO Semen parameters are as follows: Parameter Lower Reference Limit Semen volume (ml) 1.5 Sperm concentration (106/ml) 15 Total sperm number (106/ejeculate) 39 Progressive motility (PR, %) 32 Total motility (PR+NP, %) 40 Vitality (live sperms, %) 58 Sperm morphology (NF, %) 4 pH* >/=7.2 Leucocyete* (106/ml) <1 MAR/Immunobead test*(%) <50