b. 63 minutes

c. 210 minutes

d. none of the above.

**Answer:**

b. 63 minutes

**Step-by-step explanation:**

Given;

number of times the hash function is applied = 12

time taken to brute force one application, = 21 minutes

Apply proportion, bearing in mind that 4 available resources should take less time;

1 available resource ------- 21 minutes

4 available resources ------ x

Thus, x = 21 minutes / 4

When applied 12 times, the time should be

Therefore, the correct option is **B, 63 minutes**

Solve for e

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