The missing numbers in the pattern 12, 14, 17, 13, 8, 14, 21, _, _ are respectively :

The correct option is 13, 4.

To find the missing numbers in the pattern, let us analyze the given sequence of numbers:
12, 14, 17, 13, 8, 14, 21, _, _

Notice that this sequence is formed by combining two alternating patterns (two sub-sequences interleaved together):

First pattern (odd positions: 1^st, 3^rd, 5^th, 7^th, 9^th terms):
12, 17, 8, 21, _

Let us look at the operations between consecutive terms in the first pattern:
From 1^st term to 3^rd term: 12 + 5 = 17
From 3^rd term to 5^th term: 17 - 9 = 8
From 5^th term to 7^th term: 8 + 13 = 21

Notice the numbers being added and subtracted: +5, -9, +13. The magnitude increases by 4 each step (5, 9, 13), and the sign alternates (+, -, +).
Following this rule, the next operation to get the 9^th term (the second missing number) will be subtracting 17 (since 13 + 4 = 17):
$21-17=4$

Second pattern (even positions: 2^nd, 4^th, 6^th, 8^th terms):
14, 13, 14, _

Let us look at the operations between consecutive terms in the second pattern:
From 2^nd term to 4^th term: 14 - 1 = 13
From 4^th term to 6^th term: 13 + 1 = 14
From 6^th term to 8^th term (the first missing number): 14 - 1 = 13

Thus, the 8^th term is 13 and the 9^th term is 4.

Therefore, the missing numbers in the pattern are respectively 13, 4.