To answer this question, we need to understand the valid ways to declare a float.
Option A) float f = 1F; - This option is correct because it uses the "F" suffix to indicate that the number is a float literal. In Java, the default type for floating-point numbers is double, so adding the "F" suffix is necessary to explicitly declare the variable as a float.
Option B) float f = 1.0; - This option is incorrect because the literal value 1.0 is considered a double by default. To assign a double value to a float variable, you need to explicitly cast it by adding the "F" suffix, like in Option A.
Option C) float f = "1"; - This option is incorrect because it tries to assign a string literal to a float variable. In Java, you cannot directly assign a string to a float without first converting it using appropriate methods.
Option D) float f = 1.0d; - This option is incorrect because the "d" suffix indicates that the literal value is a double. As mentioned earlier, to assign a double value to a float variable, you need to explicitly cast it by adding the "F" suffix.
The correct answer is A) float f = 1F; because it correctly declares a float variable by using the "F" suffix to indicate a float literal.