import sys
input = sys.stdin.readline

mod=998244353

T=int(input())

for tests in range(T):
    A,B,K=list(map(int,input().split()))

    if B==0:
        ANS=max(0,A*K)
        print(ANS%mod)
        continue
    if A==0:
        print(0)
        continue

    if B==1:
        if A<0:
            ANS=0
        else:
            ANS=A*K

        print(ANS%mod)
        continue

    if B==-1:
        if A>0:
            ANS=A*K
        else:
            ANS=-A*(K-1)

        print(ANS%mod)
        continue

    if B>1:
        if A>0:
            ANS=A*pow(B,K-1,mod)%mod
            print(ANS%mod)
        else:
            ANS=0
            print(ANS%mod)
        continue

    if B<=-1:
        if A>0:
            if (K-1)%2==0 and K>=2:
                ANS=A*pow(B,K-1,mod)%mod
            elif (K-1)%2==1 and K>=3:
                ANS=(A+A)*pow(B,K-2,mod)%mod
            else:
                ANS=0
        else:
            if (K-1)%2==1 and K>=3:
                ANS=A*pow(B,K-1,mod)%mod
            elif (K-1)%2==0 and K>=4:
                ANS=(A+A)*pow(B,K-2,mod)%mod
            else:
                ANS=0

        print(ANS%mod)