Insert arrows to plot with multiple lines

I have a plot created with hold on. The colors of the lines are quite similar and i want to insert arrows pointing to the right gragh line.

The code to create the figure is:

    c = physconst('lightspeed'); % lightspeed
    kB = physconst('Boltzmann'); % Bolzmann Constant
    P = 101300; % dry air pressure in Pa
    ROU = 7.5;  % water vapour density in g/m^3

    Tsys = 1; % celsius, system electronic temperature , MUST CHANGE, FIND HOW TO USE
    Tother = 1; % celsius, any other additional noise source, MUST CHANGE, FIND HOW TO USE
    T0 = 296; % K, reference temperature jornet2011, TABLE I
    T = 40; % degree Celsius, MUST CHANGE, TOTAL TEMPERATURE
    %R0=[1,10,100,200,500,800,900,1000]; % meters, distances bewteen Tx,Rx maximun 1Km
    R0=[0.5,1,10,50,100];

B=900; %GHz total spectrum
Df=100;
N=400; % distance samples
R0=linspace(0,100,N); %m
beginfrq=100; %GHz
[fc] = fc_and_sub_bands(beginfrq,Df,B,N); % N is used for sub_bands

Aabs=zeros(length(fc),length(R0)); %dB, gaspl eq (10)
Aspread=zeros(length(fc),length(R0)); % dB, eq (13)
A=zeros(length(fc),length(R0));% dB total path loss
transmitance=zeros(length(fc),length(R0)); % from eq(10)
emissivity=zeros(length(fc),length(R0)); % eq(14)
Tmol=zeros(length(fc),length(R0)); % eq(15)
N_psd=zeros(length(fc),length(R0)); % from eq (17) noise power spectral density

for j=1:length(fc)
    for i=1:length(R0) 
       Aabs(j,i)=gaspl(R0(i),fc(j),T,P,ROU);
       Aspread(j,i)=20*log10((4*pi*R0(i)*fc(j))/c);
       A(j,i)=Aabs(j,i)+Aspread(j,i);
       transmitance(j,i)=1/(10^(Aabs(j,i)/10));
       emissivity(j,i)=1-transmitance(j,i);
       Tmol(j,i)=T0*emissivity(j,i);
       N_psd(j,i)=kB.*Tmol(j,i);
    end
end

figure;
hold on
for i=1:length(fc)
    plot(R0,Tmol(i,:));
end

hold off
grid on
xlabel('distance m')
ylabel('Temperature K');
legend([num2str(fc(1)./1e9),' GHz'],[num2str(fc(2)./1e9),' GHz'],[num2str(fc(3)./1e9),' GHz'],[num2str(fc(4)./1e9),' GHz'],[num2str(fc(5)./1e9),' GHz'],[num2str(fc(6)./1e9),' GHz'],[num2str(fc(7)./1e9),' GHz'],[num2str(fc(8)./1e9),' GHz'],[num2str(fc(9)./1e9),' GHz'])
title('2.1 Tmol vs distance for different f_c Df')