In which programming language is the following if statement written: "if my_var == 1: print 'Correct.'"?

The given if statement is written in Python. This is evident from several key characteristics of the syntax. In Python, the condition of the if statement is followed by a colon, which denotes the start of the subsequent block of code. Additionally, the print function in Python uses a space to separate the function from its arguments; in the example provided, it is formatted as print 'Correct.', which aligns with Python 2 syntax. It is important to note that in Python 3, the correct syntax would be print('Correct.').

The other programming languages listed have different syntax conventions for their if statements. For instance, Java and C++ require parentheses around the condition and use curly braces to define code blocks, while Ruby, although having a more similar style to Python, uses "then" or a different format for print statements. Thus, recognizing these syntactical differences reinforces the conclusion that the correct answer is Python.