public partial class Carrier
{
    public virtual ICollection<Driver> Drivers { get => _drivers ?? (_drivers = new List<Driver>()); protected set => _drivers = value; }

public partial class Driver
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }

public class CarrierDto
{
    public List<Pair<int, string>> Drivers { get; set; }

new CarrierDto
            {
                //...
                Drivers = p.Drivers.Select(d => new Pair<int, string> { Text = d.FirstName + " " + d.LastName, Value = d.Id }).ToList(),

public class AutoMapperEfCarrier : AutoMapper.Profile
{
    public AutoMapperEfCarrier()
    {
        CreateMap<Carrier, CarrierDto>()
            .ForMember(dest => dest.Drivers, opt => ?????)
            ;
    }