72 ÷ 6 = 6 × 2

12=12

Hence, option C is the correct answer.

Option A: 78 - 3 + 4 x 36 = 219 (Not possible)

Option B: 78 ÷ 3 x 4 - 36 = 68 (Not possible)

Option C: 78 ÷ 3 x 4 + 36 = 140 (True)

Hence, option C is the correct answer.

By checking option A:

Given expression is:

44 * 6 * 12 * 3 * 20

after interchanging:

44 - 6 + 12 x 3 = 20

now solve it,

44 - 6 + 12 x 3 = 20

or, 44 - 6 + 36 = 20

or, 44+30=20

or, 74=20

so, its not correct answer.

By checking option B:

Given expression is:

44 * 6 * 12 * 3 * 20

after interchanging:

44 x 6 ÷ 12 + 3 = 20

now solve it,

44 x 6 ÷ 12 + 3 = 20

here 6 is not perfectly divisible by 12, so it will result in decimal.

so, its not correct answer.

By checking option C:

Given expression is:

44 * 6 * 12 * 3 * 20

after interchanging:

44 ÷ 6 x 12 + 3 = 20

now solve it,

44 ÷ 6 x 12 + 3 = 20

here 44 is not perfectly divisible by 6, so it will result in decimal.

so, its not correct answer.

By checking option D:

Given expression is:

44 * 6 * 12 * 3 * 20

after interchanging:

44 - 6 x 12 ÷ 3 = 20

now solve it,

44 - 6 x 12 ÷ 3 = 20

or, 44 - 6 x 4 = 20

or, 44 - 24= 20

or, 20=20

so, its correct.

Hence, option D is the correct answer.

After changing the symbols,

17 × 6 + 13 – 8 (applying BODMAS)

⇒ 102 + 13 – 8

⇒ 115 – 8

⇒ 107

Hence, option B is the correct answer.
.

After replacing the # sign,

(27 + 15 – 2) ÷ 10 = 4 (BODMAS)

(42 – 2) ÷ 10 = 4

40 ÷ 10 = 4

4 = 4

Hence, option A is the correct answer.