Step 1: Read off the overlaps from the Venn diagram.
Only X & Y (not Z) = 2.5 lakh, all three X, Y and Z = 0.5 lakh, only X & Z (not Y) = 1.0 lakh, only Y & Z (not X) = 1.5 lakh.
Step 2: Find how many read only X.
Total readership of X is 8.7 lakh, and this total is made up of only X plus the overlaps that touch X: \( \text{only X} + 2.5 + 0.5 + 1.0 = 8.7 \), so only X \( = 8.7 - 4.0 = 4.7\) lakh.
Step 3: Find only Y and only Z the same way.
For Y: \( \text{only Y} + 2.5 + 0.5 + 1.5 = 9.1 \), so only Y \( = 9.1 - 4.5 = 4.6\) lakh. For Z: \( \text{only Z} + 1.0 + 0.5 + 1.5 = 5.6 \), so only Z \( = 5.6 - 3.0 = 2.6\) lakh.
Step 4: Add up every region of the Venn diagram.
At least one \( = \text{only X} + \text{only Y} + \text{only Z} + (X\cap Y) + (X\cap Z) + (Y\cap Z) + (X\cap Y\cap Z) \) \[ = 4.7 + 4.6 + 2.6 + 2.5 + 1.0 + 1.5 + 0.5 = 17.4 \]
Final Answer:
17.4 lakh people read at least one of the three newspapers, so option C is correct. \[ \boxed{17.4 \text{ lakh}} \]