The correct answer is B- 3 days.

Semen analysis is a test that measures the quality and quantity of a man's semen and sperm. The test is used to evaluate male fertility and diagnose potential male infertility issues.

One of the factors that can affect the accuracy of semen analysis is the period of abstinence, which refers to the length of time a man refrains from sexual activity or ejaculation before providing a semen sample for analysis.

If a man abstains from sexual activity for too long, the semen sample may contain an excessive amount of dead sperm, which can skew the results and make it difficult to accurately assess fertility. On the other hand, if a man does not abstain for long enough, the semen sample may contain too few sperm, which can also affect the accuracy of the results.

According to the World Health Organization (WHO) guidelines for semen analysis, the recommended period of abstinence is 2-7 days, with 3-5 days being the optimal range. This means that men should refrain from sexual activity or ejaculation for at least 2 days but no more than 7 days before providing a semen sample for analysis.

Studies have shown that longer periods of abstinence can lead to decreased sperm motility and morphology, as well as increased levels of DNA damage in sperm. For example, a study published in the Journal of Andrology found that men who abstained for more than 10 days had lower sperm motility and higher levels of DNA fragmentation compared to men who abstained for 3-4 days.

In summary, to perform semen analysis, the period of abstinence should not be more than 3-5 days, according to WHO guidelines. Longer periods of abstinence can lead to decreased sperm quality and affect the accuracy of the results.