The effect of steroid therapy is evaluated in an 8-year-old Caucasian boy being treated for fatigue and generalized edema following a "bad cold." His vitals are T 37°C, pulse 90/min, RR 20/min, and BP 110/70. Physical exam reveals the presence of mild periorbital edema and marked peripheral edema in hands and feet with the remainder of the exam within normal limits.
Lab values include
Dipstick urine protein 3+;
urine protein 50 mg/m2/hr (<40 mg/m2/hr)
Specific gravity 1030 (1008-1020)
Urine protein/creatinine ratio 2.0/mg creatinine (<0.2/mg creatinine)
Serum albumin 3.9 (5.9-8.0 mg/dL)
Cholesterol 250 (112-247 mg/dL)
Remainder of laboratory values including BUN and plasma creatinine are within normal limits.

What is the most likely diagnosis?
a. Nephrotic syndrome
b. Acute kidney injury
c. Congestive heart failure
d. Hyperlipidemia