Nilai maksimum f(x, y) = 4x + 3y pada daerah yang diarsir tersebut adalah...

From the image, the vertices are:

• $A = (3, 1)$
• $B = (6, 2)$
• $C = (7, 5)$
• $D = (5, 7)$
• $E = (2, 8)$

For vertex $A(3, 1)$:

$$f(3, 1) = 4(3) + 3(1) = 12 + 3 = 15$$

For vertex $B(6, 2)$:

$$f(6, 2) = 4(6) + 3(2) = 24 + 6 = 30$$

For vertex $C(7, 5)$:

$$f(7, 5) = 4(7) + 3(5) = 28 + 15 = 43$$

For vertex $D(5, 7)$:

$$f(5, 7) = 4(5) + 3(7) = 20 + 21 = 41$$

For vertex $E(2, 8)$:

$$f(2, 8) = 4(2) + 3(8) = 8 + 24 = 32$$

The values obtained are $15, 30, 43, 41, 32$.
The maximum value among these is 43.

The final answer is $\text{c. 43}$.