Hey there! 
2 - 4 * 6
= 2 - 24
= -22
Option A. 
7 * (5 - 2) + 6
= 7 * 3 + 6
= 21 + 6
= 27
Option A. is incorrect 
Option B. 
5 + 2 * 7 + 6
= 5 + 14 + 6
= 19 + 6
= 25
Option B. is also incorrect 
Option C. 
7 * (5 + 2) - 6
= 7 * 7 - 6
= 49 - 6
= 43
Option C. is also incorrect 
Option D. 
6 - 2 + (7 * 5)
= 6 - 2 + 35
= 4 + 35
= 39
Thus, it seems like NONE of the ABOVE is correct 
Good luck on your assignment & enjoy your day! 
~Amphitrite1040:)