#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define popcount __builtin_popcount using namespace std; typedef long long ll; typedef pair P; const ll MOD=1e9+7; ll powmod(ll a, ll k){ ll ap=a, ans=1; while(k){ if(k&1){ ans*=ap; ans%=MOD; } ap=ap*ap; ap%=MOD; k>>=1; } return ans; } ll inv(ll a){ return powmod(a, MOD-2); } ll f[400040], invf[400040]; void fac(int n){ f[0]=1; for(ll i=1; i<=n; i++) f[i]=f[i-1]*i%MOD; invf[n]=inv(f[n]); for(ll i=n-1; i>=0; i--) invf[i]=invf[i+1]*(i+1)%MOD; } ll comb(int x, int y){ if(!(0<=y && y<=x)) return 0; return f[x]*invf[y]%MOD*invf[x-y]%MOD; } int main() { ll a, b; int n, k; scanf("%lld %lld", &a, &b); scanf("%d %d", &n, &k); a%=MOD, b%=MOD; fac(2*n-1); printf("%lld\n", (a*comb(n-1, k-1)+b*comb(n-1, k-2))%MOD); ll s=comb(2*n-2, n-1), t=comb(2*n-1, n-1); printf("%lld\n", ((a*a+b*b)%MOD*s+2*a*b%MOD*(t-s+MOD))%MOD); return 0; }