A client with type 2 diabetes mellitus (DM) is admitted to the hospital for uncontrolled DM. Insulin therapy is initiated with an initial dose Isophane suspension insulin at 0800. At 1600, the client reports having diaphoresis, rapid heartbeat, and feeling shaky. Which should the nurse do first?

A Assess the client's oxygen saturation level. B Determine the client's current glucose level D Give the client skim milk and crackers. C Give the client one-half cup of fruit juice.