Let's find the number of significant figures carefully. (A) 0.0025 Leading zeros are not significant. Only the digits 2 and 5 are significant. Significant figures =2 (B) 500.0 Trailing zeros after the decimal point are significant. 500.0⟶ digits 5, 0, 0, and 0 after decimal. Significant figures =4 (C) 2.0034 All nonzero digits are significant. Zeros between nonzero digits are significant. So digits: 2,0,0,3,4⟶ all count. Significant figures = 5 Final Answer (A,B,C)⇒(2,4,5)