Which of the following is a bacterial infection that spreads through any form of unprotected sex and by skin contact? Typically, it has stages of increasingly serious symptoms. If untreated, it may affect the heart, eyes, and brain. It can be treated with antibiotics.

Choice A reason: This is not an appropriate response by the nurse, as an ultrasound is not a screening tool for spina bifida. Spina bifida is a birth defect that occurs when the spine and spinal cord do not form properly. It can be detected by a blood test that measures the level of alpha-fetoprotein (AFP) or by a detailed ultrasound that shows the spine and the brain.

Choice B reason: This is not an appropriate response by the nurse, as an ultrasound is not necessary to determine if there is more than one fetus. Multiple fetuses can be detected by other methods, such as listening to the fetal heartbeats, measuring the fundal height, or feeling the fetal movements.

Choice C reason: This is an appropriate response by the nurse, as an ultrasound assists in identifying the location of the placenta and fetus. This is important for an amniocentesis, which is a procedure that involves inserting a needle through the abdomen and the uterus to collect a sample of amniotic fluid. The ultrasound helps to guide the needle and avoid injuring the placenta or the fetus.

Choice D reason: This is not an appropriate response by the nurse, as an ultrasound is not useful for estimating fetal age at 36 weeks of gestation. Fetal age can be estimated by an ultrasound in the first trimester, when the fetus is growing at a predictable rate and has distinct features. However, in the third trimester, the fetus grows at different rates and has more variations in size and shape. Therefore, an ultrasound is less accurate and reliable for estimating fetal age at this stage.

Choice A reason: Ceftriaxone is incorrect because it is not the drug of choice for syphilis treatment. It is a cephalosporin antibiotic that can be used for other bacterial infections, such as gonorrhea, meningitis, or pneumonia.

Choice B reason: Penicillin G is correct because it is the drug of choice for syphilis treatment. It is a penicillin antibiotic that can effectively cure syphilis at any stage, except for neurosyphilis, which requires intravenous administration.

Choice C reason: Acyclovir is incorrect because it is not the drug of choice for syphilis treatment. It is an antiviral medication that can be used for viral infections, such as herpes simplex virus, varicella-zoster virus, or cytomegalovirus.

Choice D reason: Tetracycline is incorrect because it is not the drug of choice for syphilis treatment. It is a tetracycline antibiotic that can be used for other bacterial infections, such as chlamydia, acne, or Lyme disease.