Step 1: Understand the given information.
We are given the total number of donors (13\% of 4000), the female donors (10\% of 1750), and the number of male donors is the remaining value. Let's break it down:
Step 2: Calculation of the Total.
Total number of donors = 13\% of 4000 = 520.
Step 3: Calculation of Female Donors.
Female donors = 10\% of 1750 = 175.
Step 4: Calculation of Male Donors.
Male donors = 520 - 175 = 345.
Step 5: Calculation of Ratio.
The ratio of female to male donors is \( 175 : 345 \). Simplifying the ratio gives us \( 35 : 69 \), which matches option (1).
Step 6: Conclusion.
The correct ratio of female to male blood donors is 35:69, corresponding to option (1).