Final answer:
Without the correct mathematical expression involving z, we cannot accurately calculate the value when z = 2. The provided options do not align with any calculation using z = 2 based on the information given.
Step-by-step explanation:
The student is asking to find the value of an expression when z = 2. To answer this question, we need the actual mathematical expression involving z, which isn’t provided in the typo-ridden context. However, if we're to infer from the mixed information, the closest to a complete expression we have is "13 z = 2.78", which if z equals 2 would not match any of the answer options provided (a: 20 + 6, b: 22, c: 26, d: 16). Therefore, without the correct expression, it's not possible to calculate the value based on z being 2. We need the correct expression to compute the value accurately.