Final answer:
The nurse should administer Lantus and sliding scale insulin in two separate injections as they have different roles in blood glucose management and should not be mixed.
Step-by-step explanation:
The correct answer is that the nurse should administer the medications in two separate injections. Lantus (glargine) insulin is a long-acting insulin that should not be mixed in the same syringe with other insulins. It is designed to provide a consistent level of insulin over a 24-hour period.
On the other hand, a sliding scale insulin is typically a regular or rapid-acting insulin that is dosed based on blood glucose readings and is used to manage blood sugar levels after meals. Giving these insulins separately ensures that they both work as intended, with the Lantus providing a base level of insulin and the sliding scale providing additional insulin as needed.