Solution

The correct answer is 1

Key Points

• Code (formatted):

  int i, j;
  
  for (i = 1; i < 5; i += 2)          // i: 1, 3
    for (j = 1; j < i; j += 2)        // j starts at 1 for each i
      printf("%d", j);                // prints j with no spaces/newline
      

• No braces ⇒ the inner for loop is the single statement body of the outer loop, and printf is the single statement body of the inner loop.
• The inner loop re-initializes j = 1 for each value of i, and then prints all odd j values that are strictly less than i (because j += 2).

Step-by-step dry run

After i = 3, the next i would be 5, but the condition i < 5 fails, so the loops end. Only one character was printed: 1.

Important Points

• Loop bodies without braces: only the immediately following statement belongs to the loop.
• Inner loop re-initialization: j is reset to 1 for each new i.
• Strict inequality (j < i) prevents printing when i = 1, and allows only j = 1 when i = 3.
• No spaces/newline in printf("%d", j), so the output is exactly 1.