import sys
input = sys.stdin.readline
for _ in range(int(input())):
    a, b, k = map(int, input().split())
    mod = 998244353
    if b == 1 or b == 0:
        print(max(a, 0) * k % mod)
        continue
    if b == -1:
        if a >= 0:
            print(a * k % mod)
        else:
            print(- a * (k - 1) % mod)
        continue
    if a < 0:
        if b > 0:
            print(0)
        else:
            if k == 1:
                print(0)
            else:
                if k % 2 == 0:
                    print(- a * pow(-b, k-1, mod) % mod)
                else:
                    print(- 2 * a * pow(-b, k-2, mod) % mod)
    else:
        if b > 0:
            print(a * pow(b, k-1, mod) % mod)
        else:
            if k == 1:
                print(a)
            else:
                if k % 2 == 0:
                    print(a * pow(-b, k-1, mod) % mod)
                else:
                    print(2 * a * pow(-b, k-2, mod) % mod)