Final answer:
The only true condition in an if statement from the provided options is 1) i == j && i == k, as it uses comparison operators to evaluate to a boolean result.
Step-by-step explanation:
The condition in the if statement is a logical statement that determines whether the subsequent code block should be executed. In the options provided, 1) i == j && i == k is the only one that actual represents a condition as it includes a comparison operation. The '&&' operator is a logical AND which means that for the if statement to be true, both the conditions 'i == j' and 'i == k' must be true simultaneously.
Options 2) i++, 3) j--, and 4) j = i + k do not represent conditions; they are expressions that respectively increment and decrement a value, and assign the sum of two variables to a third variable.