What are the available lengths for needles mentioned?

The lengths of needles mentioned in option B, which are 5, 10, 15, and 20 cm, are commonly recognized standard lengths used in various medical and training settings. These specific lengths provide a range that accommodates different procedures and patient needs, allowing for versatility in applications such as injections, drawing blood, or other clinical procedures that may require varying depths of penetration.

Needles of these lengths are often chosen based on factors like the target site, the type of procedure being performed, and the characteristics of the patient, such as their body composition. This range is practical in ensuring that healthcare professionals have the appropriate tools at their disposal for effective and safe interventions.

In contrast, the other options present lengths that either miss the inclusion of widely used sizes or include lengths that are typically less common or not standard in practice, making them less applicable for general use in medical practices.