The major strategy used by OPEC to influence oil price is by

The major strategy used by OPEC to influence oil price is by allocating production quotas to its members. OPEC stands for the Organization of the Petroleum Exporting Countries and is a group of 13 oil-producing countries. OPEC controls a significant portion of the world's oil production and exports, which gives it a lot of influence over oil prices. One of the ways OPEC tries to stabilize oil prices is by controlling the amount of oil that its members produce. OPEC members meet regularly to decide on production levels, and each member country is assigned a production quota. When OPEC wants to increase oil prices, it may decide to reduce production quotas, which will reduce the overall supply of oil in the market, leading to an increase in prices. Conversely, when OPEC wants to lower oil prices, it may decide to increase production quotas, which will increase the overall supply of oil in the market, leading to a decrease in prices. Therefore, the correct option is "allocating production quotas to members".