According to the passage, what were dogs trained for in the past Dogs were trained for _________ in the past.

A．Tour guide and tourist.
B．Travel service agent and tourist.
C．Ticket agent and customer.
D．Hotel agent and customer.

A．The development of the markets of the company.
B．The figures of sales and profits of the company.
C．The developing plans of the company.
D．The new trading partners of the company.