getGrade(score): Given a test score in the range 0-100, return a number representing the Letter score. Any score 90-100 is an A (so return 4). Any score 80-89 is a B (return 3). Any score 70-79 is a C (return 2). Any score 60-69 is a D (return 1). Less than 60 is an F (return 0). RUBRIC: It is not enough to just solve the problem. Make sure you use PROPER INDENTATION. You MUST use CURLY BRACKETS for all loops and if/else statements. Also, the more EFFICIENT your solution, the higher your grade. If you have extraneous (superfluous / unnecessary) code, deductions will be taken.