How to create singletone pattern of the following class

I have class to create object context. To manage object creation I want to use single tone pattern. How to create following class object creation pattern as singletone in C#.

 public abstract class EFContextBase<TContext> : IDisposable where TContext : ObjectContext, new()
        {
            private TContext _dataContext;
                protected virtual TContext DataContext
            {
                get
                {
                    if ((object)this._dataContext == null)
                        this._dataContext = Activator.CreateInstance<TContext>();
                    return this._dataContext;
                }
            }

            public EFContextBase()
            {
                this.DataContext.ContextOptions.LazyLoadingEnabled = true;
            }
                public void Dispose()
            {
                this.Dispose(true);
                GC.SuppressFinalize((object)this);
            }
                private void Dispose(bool disposing)
            {
                if (!disposing || (object)this._dataContext == null)
                    return;
                this._dataContext.Dispose();
                this._dataContext = default(TContext);
            }
        }