Q1- Write a C++ code that utilizes the PTHREAD library to synchronize the action of a group of threads. Each one of these threads is responsible for printing one character of the string shown below. THIS IS A TEST You must use the following parameters: 1- Every thread is responsible for printing unique character. For example; threadl is responsible for printing T character (3 times according to their occurrence in the string). 2- You must use the Semaphores only as synchronization elements. 3- You must use the PTHREAD library to implement the actions of threads creation, synchronization, sleeping, .... 4- After it finishes, your synchronized code must output the string shown above (using multiple pthreads). Which of the following are about prefix inversion? List the letter for the choice that applies. A. Making sure that each code is length 2n, where the first half is only 1s and second only Os B. Ensuring that the synchronization code cannot be made by compositions C. Preparing a Huffman tree with a synchronization code in a leaf at the largest depth D. Having a sequence alpha-beta before synchronization in sending a message