Suppose that you are Rafi, a student of Class VI of Chattogram Collegiate School. You have been selected to visit the National Martyrs' Memorial at Savar as part of a study tour organized by your class teacher. The class has already collected some money but still needs a small additional amount. You need the Headmaster's permission and a little financial support. Prepare the required documents and responses as requested below.

a. Write a formal application to the Headmaster of your school seeking permission to go on the study tour to Savar National Martyrs' Memorial. Include date, salutation, subject line, body (reason, accompanying teacher, funds collected, amount needed), and a polite closing.

b. Write only the subject line for the above application (one concise line).

c. Write the closing signature block for the application, including your name, class, any designation (if applicable), and 'on behalf of' line.

d. Give three polite and formal phrases (in full sentences) suitable to include in a school application requesting permission and assistance.