Which of the following is a risk factor for stillbirth?

Advanced maternal age, being overweight, and nulliparity are all recognized risk factors for stillbirth, which is why the option indicating that all of these factors contribute is correct.

Advanced maternal age has been associated with various complications during pregnancy, including an increased risk of chromosomal abnormalities and placenta-related issues, both of which can elevate the risk of stillbirth.

Being overweight can lead to several health complications such as gestational diabetes and hypertension, which can adversely affect fetal well-being and increase the risk of stillbirth.

Nulliparity, or being a first-time mother, is linked to an increased risk of stillbirth due to a combination of factors including potential underlying health issues that may not have been previously identified, and the physiological changes that occur in the body during the first pregnancy.

Incorporating all these factors into consideration provides a clearer understanding that they collectively elevate the risk of stillbirth, making the choice indicating that they all contribute to be the most accurate.