dNdx c quark

Clear[cb1, cn1, cc1, cd1, cp]; 
Clear[cab1, cbb1, can1, cbn1, ca1c1, cb1c1]; 
Clear[cac1, cbc1, ccc1, cdc1, ca2c1]; 
Clear[ca1d1, cb1d1, ca2d1, cb2d1]; 
Clear[ca1p, cb1p, cap, cbp, ccp, cdp, ca2p]; 
cb1[M_] := cab1*M^cbb1; 
cab1 = 9.9; 
cbb1 = -0.13; 
cn1[M_] := can1*M^cbn1; 
can1 = 4.14; 
cbn1 = -0.148; 
cc1[M_] := ca1c1*M^cb1c1*UnitStep[M - 445] + (10^(0.92*Log[M/2.44^2]^(-0.939)^2 - 0.617*Log[M]) - 0.00791^2)*
     UnitStep[M - 50]*UnitStep[444.999 - M]; 
ca1c1 = 0.209661; 
cb1c1 = 0.0951011; 
cac1 = 0.920196; 
cbc1 = 0.00791172; 
ccc1 = -0.938521; 
cdc1 = 2.43575; 
ca2c1 = -0.617291; 
cd1[M_] := ca1d1*M^cb1d1 + ca2d1*M^cb2d1; 
ca1d1 = 1.15; 
cb1d1 = -0.632; 
ca2d1 = 0.479; 
cb2d1 = -0.0942; 
cp[M_] := ca1p*M^cb1p*UnitStep[M - 445] + (10^(2.58*Log[M/1.31^2]^(-0.883)^2 - 1.11*Log[M]) - 0.00382^2)*
     UnitStep[M - 50]*UnitStep[444.999 - M]; 
ca1p = 8.11302; 
cb1p = 0.811851; 
cap = 2.58163; 
cbp = 0.00382306; 
ccp = -0.883116; 
cdp = 1.3121; 
ca2p = -1.11089; 
Clear[logc, ctotal, M, x]; 
logc[M_, x_] = 0.0009*Log[cp[M]*(1. - x)]*x^0.5*(x^2 - 2*x + 2); 
ctotal[M_, x_] := 5.57675*Exp[(-cb1[M])*x^cn1[M] - cc1[M]/x^cd1[M] - 7.9*x^0.686] + logc[M, x];

Plot[ctotal[5000,x],{x,0.0001,1.03},PlotRange->All]