17. When you perform arithmetic operations with operands of different types, such as adding an int and a float, a. C# chooses a unifying type for the result b. you must choose a unifying type for the result c. you must provide a cast d. you receive an error message 18. Unicode is. a. an object-oriented language b, a subset of the C# language c. a 16-bit coding scheme d. another term for hexadecimal 19. Which of the following declares a variable that can hold the word computer? a. string device 'computer'; b. string device "computer"; c. char device = 'computer'; d, char device = "computer"; 20. Which of the following is the best way to compare two string variables named stringl and string2 to determine if their contents are equal? a. string1 string2 b. stringl -string2 c. Equals string (stringl, string2) d. Two of the above