Insulin contains `3.4%` suplhur.The minimum molecular mass of insulin is:

Options

A. 940
B. 350
C. 470
D. 560

Explanation

To find the minimum molecular mass of insulin given that it contains 3.4% sulfur, we can use the formula relating the percentage composition of an element in a compound to the molecular weight of that compound.

### Step-by-Step Solution:

1. **Understand the Formula**:
The percentage of an element in a compound can be expressed using the formula:
\[ \text{Percentage of Sulfur} = \left( \frac{\text{Weight of Sulfur}}{\text{Molecular Weight of Compound}} \right) \times 100 \]

2. **Identify Known Values**:
- Percentage of sulfur = 3.4%
- Atomic weight of sulfur (S) = 32 g/mol

3. **Rearrange the Formula**:
We need to find the molecular weight of insulin (let's denote it as \( M \)):
\[ 3.4 = \left( \frac{32}{M} \right) \times 100 \]

4. **Isolate \( M \)**:
Rearranging the equation to solve for \( M \):
\[ M = \frac{32 \times 100}{3.4} \]

5. **Calculate \( M \)**:
Now, perform the calculation:
\[ M = \frac{3200}{3.4} \approx 941.17 \]

6. **Determine Minimum Molecular Mass**:
Since we are looking for the minimum molecular mass, we round this value to the nearest whole number, which gives us approximately 941 g/mol. Among the options provided, the closest value is 940 g/mol.

### Final Answer:
The minimum molecular mass of insulin is approximately **940 g/mol**.

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