The correct option is C Order placed: 11 May; Delivery date: 18 Monday
The month shown in the calendar is the month of May.
The order is placed on the second Monday of the month.
As we can see in the calendar, the 4th is the first Monday of the month and 11th is the second Monday.
So, the order is placed on the 11 May.
The order will be delivered 1 week after the day the order is placed.
We know that 1 week has 7 days.
So, the order will be delivered 7 days after 11 May, i.e., 18 May, and it falls on a Monday.
So, the posters will be delivered on the 18 May, which is a Monday.