Which one of the following countries does not possess a written constitution?

مندرجہ ذیل میں سے کون سا ملک تحریری آئین نہیں رکھتا؟

Soviet Union

U.S.A.

Britain

Switzerland

Explanation

Britain is supposed to be one of only six countries that have no written constitution, the others being Israel, Libya, New Zealand, Oman and Saudi Arabia.