This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
For the following causes of sexual dysfunction, select the most likely clinical feature.Rarely indicates organic disease. 
Select and explain. 
A. loss of sexual desire, B. failure of erection with absent nocturnal penile tumescence (NPT), C. absence of emission, D. absence of orgasm with normal libido and erectile function
D: absence of orgasm with normal libido and erectile function
Answer: D: absence of orgasm with normal libido and erectile function 
Explanation: An absent orgasm, when libido and erectile function are normal, invariably indicates that organic disease is absent. Loss of desire can also be caused by psychologic disturbance, but may indicate androgen deficiency or drug effect.