To solve for \( N \) in the equation \( \frac{3}{4} \cdot N = 1 \), we need to isolate \( N \). We can do this by multiplying both sides of the equation by the multiplicative inverse of \( \frac{3}{4} \).
The multiplicative inverse of a number \( x \) is defined as \( \frac{1}{x} \). Therefore, the multiplicative inverse of \( \frac{3}{4} \) is \( \frac{4}{3} \).
Now, we can rewrite the equation:
\[ N = 1 \cdot \frac{4}{3} = \frac{4}{3} \]
Thus, \( N \) must be the multiplicative inverse of \( \frac{3}{4} \).
The correct answer is: the multiplicative inverse of \( \frac{3}{4} \).